refactor(fleet): replace dropbox protocol with universal inbox

[Wirasm]

Summary

Replace the complex dropbox messaging system (2,100 lines with task IDs, history.jsonl, flock locking, ack files) with a simpler file-based inbox protocol at ~/.kild/inbox/<project_id>/<branch>/. Net deletion of ~2,100 lines.

Changes

• Delete dropbox.rs and its CLI commands (check-queue, report)
• Add inbox.rs with streamlined read_inbox_state() and generate_prime_context()
• Extract fleet instruction generation into fleet_instructions.rs
• Simplify Claude hooks: remove Stop prompt hook, SessionStart auto-prime, check-queue from TeammateIdle, report from TaskCompleted
• Rewrite inbox/inject/prime CLI commands for the new protocol
• Add inbox path helpers to kild-paths

Files Changed

30 files changed

File list

• .claude/agents/kild-brain.md
• .claude/skills/kild/SKILL.md
• CLAUDE.md
• crates/kild-core/src/agents/mod.rs
• crates/kild-core/src/agents/registry.rs
• crates/kild-core/src/agents/types.rs
• crates/kild-core/src/sessions/create.rs
• crates/kild-core/src/sessions/daemon_request.rs
• crates/kild-core/src/sessions/daemon_spawn.rs
• crates/kild-core/src/sessions/destroy.rs
• crates/kild-core/src/sessions/dropbox.rs (deleted)
• crates/kild-core/src/sessions/fleet.rs
• crates/kild-core/src/sessions/inbox.rs (new)
• crates/kild-core/src/sessions/integrations/claude.rs
• crates/kild-core/src/sessions/integrations/fleet_instructions.rs (new)
• crates/kild-core/src/sessions/integrations/mod.rs
• crates/kild-core/src/sessions/mod.rs
• crates/kild-core/src/sessions/open.rs
• crates/kild-daemon/src/hooks/mod.rs
• crates/kild-paths/src/lib.rs
• crates/kild/src/app/daemon.rs
• crates/kild/src/app/misc.rs
• crates/kild/src/app/mod.rs
• crates/kild/src/app/tests.rs
• crates/kild/src/commands/check_queue.rs (deleted)
• crates/kild/src/commands/inbox.rs
• crates/kild/src/commands/inject.rs
• crates/kild/src/commands/mod.rs
• crates/kild/src/commands/prime.rs
• crates/kild/src/commands/report.rs (deleted)

Testing

• cargo fmt --check passes
• cargo clippy --all -- -D warnings passes
• cargo test --all passes
• cargo build --all passes

[Wirasm]

PR Review Summary — 5 Specialized Agents

Critical Issues (3 found)

Agent	Issue	Location
code-reviewer	forward_to_brain overwrites brain's task.md — every worker Stop event clobbers the brain's current task assignment via write_task("honryu", ...). The Claude Code inbox delivery (line 329) already delivers the message; this file write is a data corruption bug.	kild-daemon/src/hooks/mod.rs:314-325
code-reviewer	kild prime --json always outputs fleet: [] — hardcoded empty vec where old code populated from context. Silent data regression for scripted consumers.	kild/src/commands/prime.rs:81-87
silent-failure-hunter	handle_all_prime collects errors but always returns Ok(()) with zero exit code. Brain running kild prime --all gets truncated output with no indication of failures. Should mirror handle_all_inbox error pattern.	kild/src/commands/prime.rs:195-202

Important Issues (5 found)

Agent	Issue	Location
silent-failure-hunter	read_inbox_state silently converts ALL I/O errors (permission denied, hardware) into "unknown" status. Should only swallow NotFound, warn on other errors.	kild-core/src/sessions/inbox.rs:134-137
silent-failure-hunter	forward_to_brain spawn_blocking JoinHandle dropped — panics in brain forwarding are completely silent. Should await and log.	kild-daemon/src/hooks/mod.rs:303-353
silent-failure-hunter	ensure_inbox status file write failure only emits warn! (needs -v), no eprintln! like the directory creation failure above it.	kild-core/src/sessions/inbox.rs:77-84
code-reviewer	write_task returns Result<Option<()>, String> — breaks project error contract requiring thiserror types with KildError trait. Should use SessionError.	kild-core/src/sessions/inbox.rs:98
code-reviewer	_is_brain parameter accepted but ignored in ensure_inbox — dead API surface violating YAGNI.	kild-core/src/sessions/inbox.rs:48

Suggestions (6 found)

Agent	Suggestion	Location
type-design	Introduce WorkerStatus enum (Idle, Working, Done, Blocked, Unknown) instead of free String for InboxState::status. Prevents misspelling/casing issues.	inbox.rs:24
simplifier	Extract build_fleet_entries() and render_fleet_table() helpers — identical construction loop appears verbatim in both generate_prime_context and generate_status_table.	inbox.rs:222-236, 294-308
simplifier	Flatten write_task return type from Result<Option<()>, String> to Result<bool, String> — Option<()> carries no info, bool expresses "wrote or not" directly.	inbox.rs:98-117
simplifier	Remove _resolved wrapper functions — merge path resolution into primary read_inbox_state and generate_prime_context functions. Every caller resolves paths just to call these.	inbox.rs:334-351
simplifier	Three write_*_fleet_instructions functions are structurally identical (only file path and log label differ) — extract a shared helper.	fleet_instructions.rs:89-133
silent-failure-hunter	upsert_fleet_section silently appends when begin marker exists but end marker is missing (corrupted file). Should warn about corrupt markers to prevent snowballing duplicate sections.	fleet_instructions.rs:189-191

Documentation Issues

File	Issue	Fix
README.md:296-309	Section still says "dropbox" — "Inspect fleet dropbox state"	Change to "Inspect fleet inbox state"
README.md:304-307	Lists removed --task, --report, --status flags for kild inbox — users will get clap errors	Remove; only --json and --all remain
README.md:313	kild prime note references removed "protocol" section	Change to "Output current task + fleet status as a markdown blob"
.claude/skills/kild-wave-planner/SKILL.md:86	Maps core.fleet label to deleted dropbox.rs	Change to inbox.rs

Strengths

• Massive net deletion (-2,105 lines) — the new inbox protocol is dramatically simpler
• inbox.rs:61-71 — directory creation failure correctly handled with both warn! + eprintln!
• inject.rs:57-67 — inbox write failure treated as warning allowing Claude inbox fast-path fallback
• inject.rs:104-110 — missing daemon_session_id produces specific, actionable error message
• fleet_instructions.rs:75-86 — all instruction write failures emit both warn! + eprintln!
• Clean separation of fleet instructions into dedicated fleet_instructions.rs module

Type Design Scores

Type	Overall	Notes
InboxState	6/10	status is unvalidated String; all fields pub with no constructor
FleetEntry	6/10	Construction duplicated; untyped status strings
AgentType (modified)	9/10	Clean simplification removing unused supports_inbox()
KildPaths inbox methods	8/10	Well-encapsulated path construction

Verdict

NEEDS FIXES — 3 critical issues (brain task clobber, empty fleet JSON, silent prime errors) must be addressed before merge. The 5 important issues should also be fixed. The refactoring direction is excellent and the simplification is well-motivated.

Recommended Actions

1. Remove or redirect write_task("honryu", ...) in forward_to_brain — it silently corrupts the brain's active task
2. Populate fleet field in PrimeOutput for --json path
3. Mirror handle_all_inbox error pattern in handle_all_prime
4. Narrow unwrap_or_else in read_inbox_state to only catch NotFound
5. Address remaining important issues and consider type/simplification suggestions