feat(arcan): wire lago-knowledge into agent lifecycle (BRO-604)

[broomva]

Summary

Three-layer integration of lago-knowledge into Arcan's agent loop. Every Life/Arcan agent becomes knowledge-aware natively — no hooks, no Python, pure Rust.

Layer 1 — Knowledge Tools (agent self-directs)

• WikiSearchTool: hybrid BM25 + graph proximity search exposed as an agent tool
• WikiLintTool: knowledge graph health check exposed as an agent tool

Layer 2 — Context Compiler Block (automatic injection)

• build_knowledge_block(): assembles L0+L1 from entity pages as ContextBlock::Retrieval (~600 tokens)
• build_index_from_dir(): builds KnowledgeIndex from local .md files with backing BlobStore

Layer 3 — Lifecycle Events (observability)

• knowledge.indexed: emitted when index is built (note count + health score)
• knowledge.searched: emitted on searches (query + result count + top score)

Files changed

• arcan-lago/Cargo.toml — add lago-knowledge dependency
• arcan-lago/src/knowledge_tools.rs (new) — WikiSearchTool, WikiLintTool
• arcan-lago/src/knowledge_context.rs (new) — context block builder + index helper
• arcan-lago/src/knowledge_events.rs (new) — lifecycle event constructors
• arcan-lago/src/lib.rs — module registration + exports

Test plan

• cargo check -p arcan-lago passes
• cargo clippy -p arcan-lago — zero warnings
• 146 tests pass (145 existing + 1 fixed float comparison)
• 7 new tests (context block assembly, budget limits, event types)

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features
  • Added wiki search capability to query and retrieve ranked knowledge base results.
  • Added wiki linting tool to analyze knowledge base health and identify issues.
  • Added knowledge indexing functionality to build retrievable knowledge blocks from wiki directories.
  • Added event tracking for knowledge indexing and search operations.

[linear]

BRO-604 Wire lago-knowledge into Arcan session lifecycle (tools + context + events)

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 9ee365c6-707e-4563-ba76-877b048417b6

📥 Commits

Reviewing files that changed from the base of the PR and between a45b0e6 and 5d37bf9.

📒 Files selected for processing (5)

• crates/arcan/arcan-lago/Cargo.toml
• crates/arcan/arcan-lago/src/knowledge_context.rs
• crates/arcan/arcan-lago/src/knowledge_events.rs
• crates/arcan/arcan-lago/src/knowledge_tools.rs
• crates/arcan/arcan-lago/src/lib.rs

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📝 Walkthrough

Walkthrough

This PR introduces knowledge management integration into the arcan-lago crate by adding the lago-knowledge workspace dependency and implementing four new modules: knowledge context building from markdown files, knowledge lifecycle event generation, and two agent tools for wiki searching and linting with index access.

Changes

Cohort / File(s)	Summary
Dependency Integration crates/arcan/arcan-lago/Cargo.toml	Added lago-knowledge workspace dependency to extend available types and modules.
Knowledge Management Core crates/arcan/arcan-lago/src/knowledge_context.rs, crates/arcan/arcan-lago/src/knowledge_events.rs, crates/arcan/arcan-lago/src/knowledge_tools.rs	Introduced three new modules: knowledge_context scans markdown directories and builds retrieval context blocks with knowledge indices; knowledge_events constructs event envelopes for knowledge lifecycle tracking; knowledge_tools implements WikiSearchTool (hybrid search on knowledge index) and WikiLintTool (health reporting) as arcan agent tools.
Public API Export crates/arcan/arcan-lago/src/lib.rs	Re-exported new modules and key functions (build_knowledge_block, build_index_from_dir, WikiSearchTool, WikiLintTool) to extend crate's public interface.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~60 minutes

Possibly related issues

• Wire lago-knowledge into Arcan session lifecycle (tools + context + events) #656: This PR directly implements the integration work described in the issue, including the new Cargo dependency, knowledge_tools (WikiSearchTool/WikiLintTool), knowledge_context builders, and knowledge_events lifecycle tracking.

Possibly related PRs

• feat(lago): knowledge engine — BM25, hybrid search, lint, temporal MemCubes, ingest, life-lago skill #652: Related implementation adding arcan-arcan-lago modules that consume types and APIs from lago-knowledge (KnowledgeIndex, Bm25/Hybrid search, lint, index building).
• feat(lago): add lago wiki CLI subcommands (BRO-603) #655: Related integration of lago-knowledge functionality into a different crate (lago CLI wiki subcommands) using overlapping search, lint, and workflow capabilities.

Poem

🐰 wiggles nose excitedly
From markdown files, knowledge takes flight,
Indices bloom, search tools ignite!
Wiki linted, events tracked with care,
Knowledge flows through the agent's air! 📚✨

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feature/arcan-knowledge-integration

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