Config loading for claude-sdk-cli

[shellicar]

Closes #208

What

claude-core gains a new src/config.ts with four generic exports:

• mergeRawConfigs(home, local, options?) — deep merge with optional additivePaths for concatenating arrays rather than replacing them
• loadConfig<T>(schema, homePath, localPath, mergeOptions?) — reads home + local JSON files, merges, parses with a Zod schema
• cleanSchema — strips required, additionalProperties, and Number.MAX_SAFE_INTEGER maximums from a generated JSON schema
• generateJsonSchema(schema) — calls .toJSONSchema({ target: 'draft-07' }) and cleans the result

claude-cli now imports those from claude-core instead of owning the implementations. cleanSchema.ts is deleted. The execPermissions.approve additive-array behaviour is preserved by passing additivePaths: ['execPermissions.approve'] — the generic function has no knowledge of the field name.

claude-sdk-cli gains a proper config layer:

• src/cli-config/schema.ts — Zod schema covering model and historyReplay
• src/cli-config/consts.ts — paths to ~/.claude/sdk-config.json and ./.claude/sdk-config.json
• src/cli-config/types.ts — ResolvedSdkConfig and HistoryReplayConfig derived from the schema
• src/cli-config/loadCliConfig.ts — thin wrapper over the core loadConfig
• src/cli-config/initConfig.ts — --init-config flag; writes a default config with $schema to ~/.claude/sdk-config.json if it does not already exist
• src/cli-config/generateJsonSchema.ts — generates schema/sdk-config.schema.json at build time
• src/cli-config/SdkConfigWatcher.ts — watches both config paths and calls an onChange callback immediately when either file changes (100ms debounce)

The hardcoded src/cliConfig.ts is deleted.

Hot reload: main.ts constructs an SdkConfigWatcher with a callback that updates the model display. Changes land as soon as the debounce window expires — no need to submit a turn. While a turn is in progress the display update is deferred until the turn ends, so the model shown always matches the model the current API call is actually using. The next turn picks up the new model.

Model in query block: The 🤖 <model> line is now prepended to the query summary block so you can scroll back through history and see exactly which model produced each turn without checking the log file.

Tests

9 new tests in apps/claude-sdk-cli/test/cli-config.spec.ts covering defaults, overrides, and invalid-value fallbacks.

1 new test in AgentMessageHandler.spec.ts asserting the configured model name appears in the query block stream.

All existing tests pass: 239 in claude-cli, 362 in claude-sdk-cli.

[bananabot9000]

Well-executed config extraction 🍌 +553/-141 across 27 files, clean architecture.

Highlights:

• io: 'input' on toJSONSchema() -- the right fix, killed the cleanSchema hack
• additivePaths generalization on mergeRawConfigs -- zero knowledge of specific fields
• Zod .catch() chains for fault tolerance -- invalid config falls back to defaults
• SdkConfigWatcher encapsulation -- private fields, construct/use/dispose lifecycle
• Turn-latch pattern for model display -- prevents showing next-turn model during current execution

Items to note:

1. Two as type casts on loadConfig return -- may be hiding mismatch from $schema Omit. Worth checking if the cast is actually needed or masking a type error.
2. SdkConfigWatcher has zero test coverage -- most stateful new code (debounce, dispose, reload failure, missing-file edge case). Main risk area.
3. Watcher only watches files existing at construction time -- creating config file after startup won't trigger hot reload. Acceptable for v0, worth documenting.
4. Session log bundles context from PRs #219/#220/#222 -- not a blocker.
5. cli-config.schema.json lost required constraints on nested objects due to io: 'input' -- intentional but decreased validation strictness.

No sensitive data, no reversions.

Reviewed by BananaBot9000 🍌