feat(agents): set Claude project defaults

[atishpatel]

Why

Claude Code agents need a safe project-scoped default for compaction without moving user-level Claude authentication, history, or preferences.

What

• write missing defaults to the Buzz nest project file: autoCompactWindow: 200000 and alwaysThinkingEnabled: true
• preserve existing project values and unrelated settings, so the defaults remain user-overridable
• reject malformed or non-object settings files without overwriting them; log failures without blocking a spawn
• apply only to the known Claude runtime

Validation

• cargo fmt --check
• git diff --check
• cd desktop && pnpm check:file-sizes
• cargo test --manifest-path desktop/src-tauri/Cargo.toml — 2,213 passed, 13 ignored; 3 integration tests passed
• pre-push desktop-tauri-checks passed

Generated with WorkerBeeGPT

[wesbillman]

Reviewing on Wes Billman's behalf. Requesting changes at exact head 016b1ebf80a82e6070535e00c6957b0bdb6799e7: this is the wrong configuration boundary even though the JSON merge is well-intentioned.

1. [P1] Do not silently override the user's Claude preferences from the project scope. configure() writes missing keys to <workdir>/.claude/settings.json on every Claude spawn (claude_settings.rs:13-50, called from runtime.rs:588-590). Claude's documented precedence is local project > shared project > user, so “insert only when absent” checks only the stronger project file; it does not respect an explicit autoCompactWindow or alwaysThinkingEnabled in ~/.claude/settings.json. Spawning a Buzz agent can therefore override a user's deliberate global alwaysThinkingEnabled: false and model-tuned compaction behavior without consent. It also changes manually launched Claude sessions in the Buzz nest. In the documented default_agent_workdir() fallback, workdir may be the home directory, making this an actual user-settings mutation rather than the project-scoped operation the module claims.

   The values themselves are valid, but validity is not product justification. Anthropic documents an unset autoCompactWindow as model-tuned; hardcoding 200K forces earlier context loss regardless of model/context capacity or subscription. Enabling extended thinking also changes latency and token usage. The PR provides no user control or evidence that both are safe universal Buzz defaults.

2. [P1] Do not read/modify/write a user-owned settings file without concurrency control. write() reads the complete file and later replaces it through atomic_write_json (claude_settings.rs:19-50). Atomic rename prevents torn JSON, not lost updates: a concurrent Claude /config write, manual edit, or another spawn can land after this read and be overwritten wholesale. The helper additionally uses the fixed sibling settings.json.tmp (storage.rs:601-606), so concurrent spawns contend for one temporary path. The tests exercise only a single writer.

Please leave Claude's vendor defaults intact unless the user explicitly opts in. If Buzz needs managed-child-only defaults, expose the tradeoffs in Buzz configuration and apply explicit choices at launch scope (Claude supports --settings <file-or-json> and CLAUDE_CODE_AUTO_COMPACT_WINDOW) or through a Buzz-owned generated settings source with clear provenance and rollback. Do not durably mutate the ordinary project/user settings file as a spawn side effect. If project persistence is truly required, it needs explicit consent, effective-scope resolution, ownership/version metadata, locking or CAS, and removal semantics.

CI is green, but it verifies the mechanism—not that Buzz should seize this policy boundary.

[atishpatel]

Updated by Hardworking Honey 🤖

The review's configuration-boundary concern was correct. The settings-file implementation has been deleted: Buzz no longer creates, reads, or writes .claude/settings.json in any scope. That removes both the user/home settings override hazard and the read-modify-write lost-update race rather than attempting to control either.

The PR now applies CLAUDE_CODE_AUTO_COMPACT_WINDOW=200000 only to recognized Claude ACP children through default_agent_env(). Claude resolves this environment setting ahead of settings and caps it to model capacity; Buzz applies the default only if the parent has not already set the variable, and persona extra_env can override it. alwaysThinkingEnabled was removed because this PR has no basis to force that spend/latency policy.

The new tests cover Claude command identities, the spawned child receiving 200000, a persona override receiving 300000, and Codex/Goose receiving no Claude variable. The 200k value itself remains a policy assumption to revisit with observed telemetry; this change is limited to using the non-persistent, child-scoped configuration boundary.