appconfig: add comprehensive tests; achieve >80% coverage for package

3 files changed, 167 insertions, 698 deletions

diff --git a/UNITTESTSTOADD.md b/UNITTESTSTOADD.md
deleted file mode 100644
index 2ebcd02..0000000
--- a/UNITTESTSTOADD.md
+++ /dev/null
@@ -1,511 +0,0 @@
-# Unit tests to consider adding
-
-This report lists functions that do not appear to be referenced in test files in the same package directory. Recommendations are heuristic.
-
-## main (cmd/hexai-lsp)
-
-- cmd/hexai-lsp/main.go — func main
-  - exported: false  complexity: 5  has-control: true
-  - recommendation: add test (non-trivial logic)
-
-## hexaicli (internal/hexaicli)
-
-- internal/hexaicli/run.go — func Run
-  - exported: true  complexity: 5  has-control: true
-  - recommendation: add test (exported)
-- internal/hexaicli/run.go — func newClientFromConfig
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (non-trivial logic)
-
-## llm (internal/llm)
-
-- internal/llm/copilot.go — method (copilotClient).Chat
-  - exported: true  complexity: 24  has-control: true
-  - recommendation: add test (exported)
-- internal/llm/copilot.go — method (copilotClient).CodeCompletion
-  - exported: true  complexity: 18  has-control: true
-  - recommendation: add test (exported)
-- internal/llm/copilot.go — method (copilotClient).DefaultModel
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/copilot.go — method (copilotClient).Name
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/copilot.go — func decodeCopilotChat
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/copilot.go — method (copilotClient).ensureSession
-  - exported: false  complexity: 19  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/copilot.go — func handleCopilotNon2xx
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/copilot.go — method (copilotClient).headersChat
-  - exported: false  complexity: 3  has-control: false
-  - recommendation: add test (non-trivial logic)
-- internal/llm/copilot.go — method (copilotClient).headersGhost
-  - exported: false  complexity: 3  has-control: false
-  - recommendation: add test (non-trivial logic)
-- internal/llm/copilot.go — func newCopilot
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/copilot.go — func parseInt64
-  - exported: false  complexity: 3  has-control: false
-  - recommendation: add test (non-trivial logic)
-- internal/llm/copilot.go — func parseJWTExp
-  - exported: false  complexity: 8  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/copilot.go — method (copilotClient).postJSON
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/copilot.go — func randHex
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/ollama.go — method (ollamaClient).Chat
-  - exported: true  complexity: 20  has-control: true
-  - recommendation: add test (exported)
-- internal/llm/ollama.go — method (ollamaClient).ChatStream
-  - exported: true  complexity: 18  has-control: true
-  - recommendation: add test (exported)
-- internal/llm/ollama.go — method (ollamaClient).DefaultModel
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/ollama.go — method (ollamaClient).Name
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/ollama.go — method (ollamaClient).doJSON
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/ollama.go — func handleOllamaNon2xx
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/ollama.go — method (ollamaClient).logStart
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/ollama.go — func newOllama
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/openai.go — method (openAIClient).Chat
-  - exported: true  complexity: 21  has-control: true
-  - recommendation: add test (exported)
-- internal/llm/openai.go — method (openAIClient).ChatStream
-  - exported: true  complexity: 18  has-control: true
-  - recommendation: add test (exported)
-- internal/llm/openai.go — method (openAIClient).DefaultModel
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/openai.go — method (openAIClient).Name
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/openai.go — func decodeOpenAIChat
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/openai.go — method (openAIClient).doJSON
-  - exported: false  complexity: 5  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/openai.go — method (openAIClient).doJSONWithAccept
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/openai.go — method (openAIClient).logStart
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/openai.go — method (openAIClient).logf
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: optional (helper/trivial)
-- internal/llm/openai.go — func newOpenAI
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/llm/provider.go — func NewFromConfig
-  - exported: true  complexity: 3  has-control: true
-  - recommendation: add test (exported)
-- internal/llm/provider.go — func WithMaxTokens
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/provider.go — func WithModel
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/provider.go — func WithStop
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/provider.go — func WithTemperature
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/llm/util.go — func nilStringErr
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: optional (helper/trivial)
-
-## lsp (internal/lsp)
-
-- internal/lsp/context.go — method (Server).fullFileContext
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/document.go — method (Server).deleteDocument
-  - exported: false  complexity: 3  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/document.go — method (Server).getDocument
-  - exported: false  complexity: 3  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/document.go — func hasAny
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/document.go — method (Server).isDefiningNewFunction
-  - exported: false  complexity: 10  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers.go — method (Server).compCacheTouchLocked
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers.go — method (Server).completionCacheGet
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers.go — method (Server).completionCacheKey
-  - exported: false  complexity: 13  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers.go — method (Server).completionCachePut
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers.go — method (Server).fallbackCompletionItems
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers.go — method (Server).handle
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers.go — func instructionFromSelection
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers.go — method (Server).isTriggerEvent
-  - exported: false  complexity: 7  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers.go — method (Server).makeCompletionItems
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers.go — method (Server).reply
-  - exported: false  complexity: 2  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_codeaction.go — method (Server).buildDocumentCodeAction
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_codeaction.go — method (Server).buildGoUnitTestCodeAction
-  - exported: false  complexity: 9  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_codeaction.go — func deriveGoFuncName
-  - exported: false  complexity: 7  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_codeaction.go — method (Server).diagnosticsInRange
-  - exported: false  complexity: 7  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_codeaction.go — func exportName
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_codeaction.go — func fileExists
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_codeaction.go — func findGoFunctionAtLine
-  - exported: false  complexity: 10  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_codeaction.go — method (Server).generateGoTestFunction
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_codeaction.go — func greaterPos
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_codeaction.go — method (Server).handleCodeAction
-  - exported: false  complexity: 11  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_codeaction.go — method (Server).handleCodeActionResolve
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_codeaction.go — func lessPos
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_codeaction.go — method (Server).loadFileText
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_codeaction.go — func parseGoPackageName
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_codeaction.go — func rangesOverlap
-  - exported: false  complexity: 5  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_codeaction.go — method (Server).resolveGoTest
-  - exported: false  complexity: 30  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — method (Server).buildCompletionMessages
-  - exported: false  complexity: 5  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — method (Server).buildDocString
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — func extractTriggerInfo
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_completion.go — method (Server).handleCompletion
-  - exported: false  complexity: 5  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — method (Server).logCompletionContext
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — func parseManualInvoke
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_completion.go — method (Server).postProcessCompletion
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — method (Server).prefixHeuristicAllows
-  - exported: false  complexity: 11  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — method (Server).shouldSuppressForChatTriggerEOL
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — method (Server).tryProviderNativeCompletion
-  - exported: false  complexity: 18  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — method (Server).waitForDebounce
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_completion.go — method (Server).waitForThrottle
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).applyChatEdits
-  - exported: false  complexity: 10  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).buildChatHistory
-  - exported: false  complexity: 10  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).clientApplyEdit
-  - exported: false  complexity: 6  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).clientShowDocument
-  - exported: false  complexity: 9  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).deferShowDocument
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).detectAndHandleChat
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).docBeforeAfter
-  - exported: false  complexity: 16  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).handleDidChange
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).handleDidClose
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).handleDidOpen
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — method (Server).nextReqID
-  - exported: false  complexity: 6  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_document.go — func stripTrailingTrigger
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_execute.go — method (Server).handleExecuteCommand
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_init.go — method (Server).handleExit
-  - exported: false  complexity: 2  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_init.go — method (Server).handleInitialize
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_init.go — method (Server).handleInitialized
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_init.go — method (Server).handleShutdown
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_utils.go — func applyIndent
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — func buildPrompts
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — method (Server).collectPromptRemovalEdits
-  - exported: false  complexity: 5  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_utils.go — func computeTextEditAndFilter
-  - exported: false  complexity: 5  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — func computeWordStart
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — func extractRangeText
-  - exported: false  complexity: 13  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — func inParamList
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — method (Server).incRecvCounters
-  - exported: false  complexity: 4  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_utils.go — method (Server).incSentCounters
-  - exported: false  complexity: 4  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_utils.go — func isBareDoubleSemicolon
-  - exported: false  complexity: 5  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — func isIdentBoundary
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: optional (helper/trivial)
-- internal/lsp/handlers_utils.go — func isIdentChar
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: optional (helper/trivial)
-- internal/lsp/handlers_utils.go — func labelForCompletion
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — func leadingIndent
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — func lineHasInlinePrompt
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/lsp/handlers_utils.go — method (Server).llmRequestOpts
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/handlers_utils.go — method (Server).logLLMStats
-  - exported: false  complexity: 13  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/server.go — method (Server).Run
-  - exported: true  complexity: 1  has-control: true
-  - recommendation: add test (exported)
-- internal/lsp/transport.go — method (Server).readMessage
-  - exported: false  complexity: 7  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/lsp/transport.go — method (Server).writeMessage
-  - exported: false  complexity: 5  has-control: true
-  - recommendation: add test (exported receiver)
-
-## main (scripts)
-
-- scripts/scan_uncovered.go — func isExportedIdent
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- scripts/scan_uncovered.go — func main
-  - exported: false  complexity: 12  has-control: true
-  - recommendation: add test (non-trivial logic)
-- scripts/scan_uncovered.go — func recommend
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-- scripts/scan_uncovered.go — func relPath
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (non-trivial logic)
-- scripts/scan_uncovered.go — func typeString
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: optional (helper/trivial)
-
-## appconfig (internal/appconfig)
-
-- internal/appconfig/config.go — func Load
-  - exported: true  complexity: 6  has-control: true
-  - recommendation: add test (exported)
-- internal/appconfig/config.go — func getConfigPath
-  - exported: false  complexity: 3  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/appconfig/config.go — func loadFromEnv
-  - exported: false  complexity: 27  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/appconfig/config.go — func loadFromFile
-  - exported: false  complexity: 7  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/appconfig/config.go — method (App).mergeBasics
-  - exported: false  complexity: 11  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/appconfig/config.go — method (App).mergeProviderFields
-  - exported: false  complexity: 9  has-control: true
-  - recommendation: add test (exported receiver)
-- internal/appconfig/config.go — method (App).mergeWith
-  - exported: false  complexity: 2  has-control: false
-  - recommendation: add test (exported receiver)
-- internal/appconfig/config.go — func newDefaultConfig
-  - exported: false  complexity: 2  has-control: false
-  - recommendation: optional (helper/trivial)
-
-## hexailsp (internal/hexailsp)
-
-- internal/hexailsp/run.go — func buildClientIfNil
-  - exported: false  complexity: 7  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/hexailsp/run.go — func ensureFactory
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (non-trivial logic)
-- internal/hexailsp/run.go — func makeServerOptions
-  - exported: false  complexity: 1  has-control: false
-  - recommendation: optional (helper/trivial)
-- internal/hexailsp/run.go — func normalizeLoggingConfig
-  - exported: false  complexity: 2  has-control: true
-  - recommendation: add test (non-trivial logic)
-
-## logging (internal/logging)
-
-- internal/logging/chatlogger.go — method (ChatLogger).LogStart
-  - exported: true  complexity: 4  has-control: true
-  - recommendation: add test (exported)
-- internal/logging/chatlogger.go — func NewChatLogger
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/logging/logging.go — func Bind
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- internal/logging/logging.go — func Logf
-  - exported: true  complexity: 3  has-control: true
-  - recommendation: add test (exported)
-- internal/logging/logging.go — func PreviewForLog
-  - exported: true  complexity: 2  has-control: true
-  - recommendation: add test (exported)
-- internal/logging/logging.go — func SetLogPreviewLimit
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-
-## main (.)
-
-- Magefile.go — func Build
-  - exported: true  complexity: 3  has-control: false
-  - recommendation: add test (exported)
-- Magefile.go — func BuildHexaiCLI
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- Magefile.go — func BuildHexaiLSP
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- Magefile.go — func Cover
-  - exported: true  complexity: 10  has-control: true
-  - recommendation: add test (exported)
-- Magefile.go — func CoverAll
-  - exported: true  complexity: 10  has-control: true
-  - recommendation: add test (exported)
-- Magefile.go — func Dev
-  - exported: true  complexity: 3  has-control: true
-  - recommendation: add test (exported)
-- Magefile.go — func DevInstall
-  - exported: true  complexity: 2  has-control: true
-  - recommendation: add test (exported)
-- Magefile.go — func Install
-  - exported: true  complexity: 7  has-control: true
-  - recommendation: add test (exported)
-- Magefile.go — func Lint
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- Magefile.go — func RunCLI
-  - exported: true  complexity: 3  has-control: false
-  - recommendation: add test (exported)
-- Magefile.go — func Test
-  - exported: true  complexity: 2  has-control: true
-  - recommendation: add test (exported)
-- Magefile.go — func Vet
-  - exported: true  complexity: 1  has-control: false
-  - recommendation: add test (exported)
-- Magefile.go — func totalCoveragePercent
-  - exported: false  complexity: 8  has-control: true
-  - recommendation: add test (non-trivial logic)
-- Magefile.go — func warnIfLowCoverage
-  - exported: false  complexity: 6  has-control: true
-  - recommendation: add test (non-trivial logic)
-
-## main (cmd/hexai)
-
-- cmd/hexai/main.go — func main
-  - exported: false  complexity: 4  has-control: true
-  - recommendation: add test (non-trivial logic)
-
diff --git a/internal/appconfig/config_test.go b/internal/appconfig/config_test.go
new file mode 100644
index 0000000..30898a6
--- /dev/null
+++ b/internal/appconfig/config_test.go
@@ -0,0 +1,167 @@
+package appconfig
+
+import (
+    "encoding/json"
+    "io"
+    "log"
+    "os"
+    "path/filepath"
+    "reflect"
+    "strings"
+    "testing"
+)
+
+func newLogger() *log.Logger { return log.New(io.Discard, "", 0) }
+
+func writeJSON(t *testing.T, path string, v any) {
+    t.Helper()
+    if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+        t.Fatalf("mkdir: %v", err)
+    }
+    f, err := os.Create(path)
+    if err != nil { t.Fatalf("create: %v", err) }
+    defer f.Close()
+    enc := json.NewEncoder(f)
+    if err := enc.Encode(v); err != nil {
+        t.Fatalf("encode json: %v", err)
+    }
+}
+
+func withEnv(t *testing.T, k, v string) { t.Helper(); old := os.Getenv(k); _ = os.Setenv(k, v); t.Cleanup(func(){ _ = os.Setenv(k, old) }) }
+
+func TestLoad_Defaults_NoLogger(t *testing.T) {
+    cfg := Load(nil)
+    if cfg.MaxTokens == 0 || cfg.ContextMode == "" || cfg.ContextWindowLines == 0 || cfg.MaxContextTokens == 0 {
+        t.Fatalf("expected defaults populated, got %+v", cfg)
+    }
+    if cfg.CodingTemperature == nil { t.Fatalf("expected default CodingTemperature") }
+}
+
+func TestLoad_Defaults_WithLogger_NoFile_NoEnv(t *testing.T) {
+    t.Setenv("XDG_CONFIG_HOME", t.TempDir())
+    logger := newLogger()
+    cfg := Load(logger)
+    def := newDefaultConfig()
+    if cfg.MaxTokens != def.MaxTokens || cfg.ContextMode != def.ContextMode || cfg.ContextWindowLines != def.ContextWindowLines {
+        t.Fatalf("expected defaults; got %+v want %+v", cfg, def)
+    }
+}
+
+func TestLoad_FileMerge_And_EnvOverride(t *testing.T) {
+    dir := t.TempDir()
+    t.Setenv("XDG_CONFIG_HOME", dir)
+    cfgPath := filepath.Join(dir, "hexai", "config.json")
+    temp0 := 0.0
+    fileCfg := App{
+        MaxTokens: 123,
+        ContextMode: "file-on-new-func",
+        ContextWindowLines: 50,
+        MaxContextTokens: 999,
+        LogPreviewLimit: 0,
+        CodingTemperature: &temp0,
+        ManualInvokeMinPrefix: 2,
+        CompletionDebounceMs: 150,
+        CompletionThrottleMs: 300,
+        TriggerCharacters: []string{".", ":"},
+        Provider: "openai",
+        OpenAIBaseURL: "https://api.example",
+        OpenAIModel: "gpt-x",
+        OpenAITemperature: &temp0,
+        OllamaBaseURL: "http://ollama",
+        OllamaModel: "llama",
+        OllamaTemperature: &temp0,
+        CopilotBaseURL: "http://copilot",
+        CopilotModel: "ghost",
+        CopilotTemperature: &temp0,
+    }
+    writeJSON(t, cfgPath, fileCfg)
+
+    // Env overrides take precedence
+    withEnv(t, "HEXAI_MAX_TOKENS", "321")
+    withEnv(t, "HEXAI_CONTEXT_MODE", "always-full")
+    withEnv(t, "HEXAI_CONTEXT_WINDOW_LINES", "77")
+    withEnv(t, "HEXAI_MAX_CONTEXT_TOKENS", "888")
+    withEnv(t, "HEXAI_LOG_PREVIEW_LIMIT", "7")
+    withEnv(t, "HEXAI_CODING_TEMPERATURE", "0.7")
+    withEnv(t, "HEXAI_MANUAL_INVOKE_MIN_PREFIX", "5")
+    withEnv(t, "HEXAI_COMPLETION_DEBOUNCE_MS", "333")
+    withEnv(t, "HEXAI_COMPLETION_THROTTLE_MS", "444")
+    withEnv(t, "HEXAI_TRIGGER_CHARACTERS", "., / ,_")
+    withEnv(t, "HEXAI_PROVIDER", "ollama")
+    withEnv(t, "HEXAI_OPENAI_BASE_URL", "https://override")
+    withEnv(t, "HEXAI_OPENAI_MODEL", "gpt-override")
+    withEnv(t, "HEXAI_OPENAI_TEMPERATURE", "0.4")
+    withEnv(t, "HEXAI_OLLAMA_BASE_URL", "http://ollama-override")
+    withEnv(t, "HEXAI_OLLAMA_MODEL", "mistral")
+    withEnv(t, "HEXAI_OLLAMA_TEMPERATURE", "0.6")
+    withEnv(t, "HEXAI_COPILOT_BASE_URL", "http://copilot-override")
+    withEnv(t, "HEXAI_COPILOT_MODEL", "ghost-override")
+    withEnv(t, "HEXAI_COPILOT_TEMPERATURE", "0.3")
+
+    logger := newLogger()
+    cfg := Load(logger)
+
+    // Check overrides
+    if cfg.MaxTokens != 321 || cfg.ContextMode != "always-full" || cfg.ContextWindowLines != 77 || cfg.MaxContextTokens != 888 {
+        t.Fatalf("env overrides (basic) not applied: %+v", cfg)
+    }
+    if cfg.LogPreviewLimit != 7 || cfg.ManualInvokeMinPrefix != 5 || cfg.CompletionDebounceMs != 333 || cfg.CompletionThrottleMs != 444 {
+        t.Fatalf("env overrides (ints) not applied: %+v", cfg)
+    }
+    if cfg.CodingTemperature == nil || *cfg.CodingTemperature != 0.7 {
+        t.Fatalf("env override (CodingTemperature) not applied: %+v", cfg.CodingTemperature)
+    }
+    if want := []string{".", "/", "_"}; !reflect.DeepEqual(cfg.TriggerCharacters, want) {
+        t.Fatalf("env override (TriggerCharacters), got %v want %v", cfg.TriggerCharacters, want)
+    }
+    if cfg.Provider != "ollama" {
+        t.Fatalf("provider override failed: %q", cfg.Provider)
+    }
+    // Provider-specific
+    if cfg.OpenAIBaseURL != "https://override" || cfg.OpenAIModel != "gpt-override" || cfg.OpenAITemperature == nil || *cfg.OpenAITemperature != 0.4 {
+        t.Fatalf("openai overrides not applied: %+v", cfg)
+    }
+    if cfg.OllamaBaseURL != "http://ollama-override" || cfg.OllamaModel != "mistral" || cfg.OllamaTemperature == nil || *cfg.OllamaTemperature != 0.6 {
+        t.Fatalf("ollama overrides not applied: %+v", cfg)
+    }
+    if cfg.CopilotBaseURL != "http://copilot-override" || cfg.CopilotModel != "ghost-override" || cfg.CopilotTemperature == nil || *cfg.CopilotTemperature != 0.3 {
+        t.Fatalf("copilot overrides not applied: %+v", cfg)
+    }
+
+    // Ensure file values would have applied absent env
+    // Spot-check: reset env and reload
+    for _, k := range []string{
+        "HEXAI_MAX_TOKENS","HEXAI_CONTEXT_MODE","HEXAI_CONTEXT_WINDOW_LINES","HEXAI_MAX_CONTEXT_TOKENS","HEXAI_LOG_PREVIEW_LIMIT","HEXAI_CODING_TEMPERATURE","HEXAI_MANUAL_INVOKE_MIN_PREFIX","HEXAI_COMPLETION_DEBOUNCE_MS","HEXAI_COMPLETION_THROTTLE_MS","HEXAI_TRIGGER_CHARACTERS","HEXAI_PROVIDER","HEXAI_OPENAI_BASE_URL","HEXAI_OPENAI_MODEL","HEXAI_OPENAI_TEMPERATURE","HEXAI_OLLAMA_BASE_URL","HEXAI_OLLAMA_MODEL","HEXAI_OLLAMA_TEMPERATURE","HEXAI_COPILOT_BASE_URL","HEXAI_COPILOT_MODEL","HEXAI_COPILOT_TEMPERATURE",
+    } { t.Setenv(k, "") }
+    cfg2 := Load(logger)
+    if cfg2.MaxTokens != 123 || cfg2.ContextMode != "file-on-new-func" || cfg2.ContextWindowLines != 50 || cfg2.MaxContextTokens != 999 || cfg2.LogPreviewLimit != 0 {
+        t.Fatalf("file merge not applied: %+v", cfg2)
+    }
+    if cfg2.CodingTemperature == nil || *cfg2.CodingTemperature != 0.0 {
+        t.Fatalf("file merge (CodingTemperature) not applied: %+v", cfg2.CodingTemperature)
+    }
+    if cfg2.OpenAIBaseURL != "https://api.example" || cfg2.OpenAIModel != "gpt-x" || cfg2.OpenAITemperature == nil || *cfg2.OpenAITemperature != 0.0 {
+        t.Fatalf("file merge (openai) not applied: %+v", cfg2)
+    }
+}
+
+func TestGetConfigPath_XDG(t *testing.T) {
+    dir := t.TempDir()
+    t.Setenv("XDG_CONFIG_HOME", dir)
+    path, err := getConfigPath()
+    if err != nil { t.Fatalf("getConfigPath: %v", err) }
+    if !strings.HasPrefix(path, filepath.Join(dir, "hexai")) || !strings.HasSuffix(path, "config.json") {
+        t.Fatalf("unexpected path: %s", path)
+    }
+}
+
+func TestLoadFromFile_InvalidJSON(t *testing.T) {
+    dir := t.TempDir()
+    t.Setenv("XDG_CONFIG_HOME", dir)
+    cfgPath := filepath.Join(dir, "hexai", "config.json")
+    if err := os.MkdirAll(filepath.Dir(cfgPath), 0o755); err != nil { t.Fatal(err) }
+    if err := os.WriteFile(cfgPath, []byte("{ invalid"), 0o644); err != nil { t.Fatal(err) }
+    _, err := loadFromFile(cfgPath, newLogger())
+    if err == nil { t.Fatalf("expected error for invalid JSON") }
+}
+
diff --git a/scripts/scan_uncovered.go b/scripts/scan_uncovered.go
deleted file mode 100644
index 9eb22fd..0000000
--- a/scripts/scan_uncovered.go
+++ /dev/null
@@ -1,187 +0,0 @@
-// Command scan_uncovered analyzes Go source to find functions without tests
-// and recommends whether to add tests based on export status and basic complexity.
-package main
-
-import (
-    "fmt"
-    "go/ast"
-    "go/parser"
-    "go/token"
-    "os"
-    "path/filepath"
-    "sort"
-    "strings"
-)
-
-type FuncInfo struct {
-    File    string
-    Package string
-    Name    string
-    Recv    string // receiver type for methods
-    Exported bool
-    Complexity int // naive: number of statements in body
-    HasControl bool // has if/for/switch/select
-}
-
-func main() {
-    root := "."
-    dirs := map[string][]string{}
-    _ = filepath.WalkDir(root, func(path string, d os.DirEntry, err error) error {
-        if err != nil { return nil }
-        // Skip vendor, tmp, .git, node_modules, build caches
-        base := filepath.Base(path)
-        if d.IsDir() {
-            if (path != "." && strings.HasPrefix(base, ".")) || base == "vendor" || base == "tmp" || base == "node_modules" || base == ".gocache" || base == ".gomodcache" {
-                return filepath.SkipDir
-            }
-            return nil
-        }
-        if strings.HasSuffix(path, ".go") && !strings.HasSuffix(path, "_test.go") {
-            dir := filepath.Dir(path)
-            dirs[dir] = append(dirs[dir], path)
-        }
-        return nil
-    })
-
-    fset := token.NewFileSet()
-    type missing struct{
-        pkg string
-        dir string
-        items []FuncInfo
-    }
-    var all []missing
-
-    for dir, files := range dirs {
-        // parse package name from any file
-        pkg := ""
-        var funcs []FuncInfo
-        for _, file := range files {
-            f, err := parser.ParseFile(fset, file, nil, 0)
-            if err != nil { continue }
-            if pkg == "" { pkg = f.Name.Name }
-            for _, d := range f.Decls {
-                fd, ok := d.(*ast.FuncDecl)
-                if !ok || fd.Name == nil { continue }
-                // Skip init/test helpers in non-test files? keep all funcs
-                info := FuncInfo{File: file, Package: pkg, Name: fd.Name.Name, Exported: ast.IsExported(fd.Name.Name)}
-                if fd.Recv != nil && len(fd.Recv.List) > 0 {
-                    info.Recv = typeString(fd.Recv.List[0].Type)
-                }
-                if fd.Body != nil {
-                    info.Complexity = len(fd.Body.List)
-                    ast.Inspect(fd.Body, func(n ast.Node) bool {
-                        switch n.(type) {
-                        case *ast.IfStmt, *ast.ForStmt, *ast.RangeStmt, *ast.SwitchStmt, *ast.SelectStmt:
-                            info.HasControl = true
-                        }
-                        return true
-                    })
-                }
-                funcs = append(funcs, info)
-            }
-        }
-        if len(funcs) == 0 { continue }
-        // Gather test identifiers and test names in this dir
-        testIdents := make(map[string]struct{})
-        testNames := make(map[string]struct{})
-        _ = filepath.WalkDir(dir, func(p string, d os.DirEntry, err error) error {
-            if err != nil { return nil }
-            if d.IsDir() { return nil }
-            if !strings.HasSuffix(p, "_test.go") { return nil }
-            tf, err := parser.ParseFile(fset, p, nil, 0)
-            if err != nil { return nil }
-            for _, d := range tf.Decls {
-                if fd, ok := d.(*ast.FuncDecl); ok && fd.Name != nil {
-                    if strings.HasPrefix(fd.Name.Name, "Test") { testNames[fd.Name.Name] = struct{}{} }
-                }
-            }
-            ast.Inspect(tf, func(n ast.Node) bool {
-                switch x := n.(type) {
-                case *ast.Ident:
-                    testIdents[x.Name] = struct{}{}
-                case *ast.SelectorExpr:
-                    testIdents[x.Sel.Name] = struct{}{}
-                }
-                return true
-            })
-            return nil
-        })
-
-        // Filter funcs missing coverage signal
-        var miss []FuncInfo
-        for _, fn := range funcs {
-            // Heuristic: if function name appears in tests, assume covered
-            if _, ok := testIdents[fn.Name]; ok { continue }
-            // Methods: also consider receiver type name for TestType_Method style
-            if fn.Recv != "" {
-                // e.g., TestType_Method often contains Method name as Ident; already covered by above
-            }
-            // Skip generated or trivial files? we'll decide in recommendation
-            miss = append(miss, fn)
-        }
-        if len(miss) == 0 { continue }
-        sort.Slice(miss, func(i, j int) bool {
-            if miss[i].File == miss[j].File {
-                return miss[i].Name < miss[j].Name
-            }
-            return miss[i].File < miss[j].File
-        })
-        all = append(all, missing{pkg: pkg, dir: dir, items: miss})
-    }
-
-    // Write markdown report to stdout
-    fmt.Println("# Unit tests to consider adding")
-    fmt.Println()
-    fmt.Println("This report lists functions that do not appear to be referenced in test files in the same package directory. Recommendations are heuristic.")
-    fmt.Println()
-    for _, m := range all {
-        fmt.Printf("## %s (%s)\n\n", m.pkg, m.dir)
-        for _, fn := range m.items {
-            rec := recommend(fn)
-            var sig string
-            if fn.Recv != "" { sig = fmt.Sprintf("method (%s).%s", fn.Recv, fn.Name) } else { sig = "func " + fn.Name }
-            fmt.Printf("- %s — %s\n", relPath(fn.File), sig)
-            fmt.Printf("  - exported: %t  complexity: %d  has-control: %t\n", fn.Exported, fn.Complexity, fn.HasControl)
-            fmt.Printf("  - recommendation: %s\n", rec)
-        }
-        fmt.Println()
-    }
-}
-
-func typeString(t ast.Expr) string {
-    switch x := t.(type) {
-    case *ast.Ident:
-        return x.Name
-    case *ast.StarExpr:
-        return typeString(x.X)
-    case *ast.IndexExpr:
-        return typeString(x.X)
-    case *ast.IndexListExpr:
-        return typeString(x.X)
-    case *ast.SelectorExpr:
-        return x.Sel.Name
-    default:
-        return ""
-    }
-}
-
-func recommend(fn FuncInfo) string {
-    // Strongly recommend for exported functions and methods on exported types
-    if fn.Exported { return "add test (exported)" }
-    if fn.Recv != "" && isExportedIdent(fn.Recv) { return "add test (exported receiver)" }
-    // Recommend for functions with control flow or non-trivial body
-    if fn.HasControl || fn.Complexity >= 3 { return "add test (non-trivial logic)" }
-    // Otherwise, optional
-    return "optional (helper/trivial)"
-}
-
-func isExportedIdent(name string) bool {
-    if name == "" { return false }
-    r := []rune(name)
-    return r[0] >= 'A' && r[0] <= 'Z'
-}
-
-func relPath(p string) string {
-    if rp, err := filepath.Rel(".", p); err == nil { return rp }
-    return p
-}