[LinuxDevil]

What

• Two new typed stream events, compaction.start (strategy, tokensBefore, contextWindow, thresholdTokens) and compaction.done (strategy, tokensBefore, tokensAfter, prunedToolCallIds, summary?: boolean, error?: { message }), emitted into agent.stream() / session.stream() / AgentExecutor.stream() inside the step, before the model call that triggered them. Every start has exactly one done; error is set when the strategy fails and the hook falls back.
• Minimal emit plumbing: optional GenerateHookContext.emit(event) (set only in streamed runs), backed by a new hookEvent on the internal RunEventSink; sub-agent events are tagged with subagent.
• createAgent({ compaction }): true installs the prune hook with defaults; an object takes strategy, thresholdPercent, contextWindow, protectedTokens and summarizer ('provider/model' or LLMProvider, which selects twoPhaseStrategy). summarizer together with strategy is a ConfigurationError.
• createAgent({ hooks }) (was missing): any AgentHook[], run in order before the compaction hook; also used when resuming after approval.

Why

Finishes compaction parity (LOU-W2/W3): the hook existed but could only be observed through onCompaction and could not be configured on createAgent(). Additive: event schema stays v1.

Acceptance criteria

• compaction.start / compaction.done emitted whenever the hook compacts, including compaction.done with error on strategy failure/fallback
• createAgent({ compaction?: boolean | {...} }), with summarizer selecting twoPhaseStrategy
• createAgent({ hooks }) added
• Tests with mockModel: event order around the triggering model call, compaction: true compacts a long transcript, summarizer provider is used (instance and 'provider/model'), failing strategy and failing summarizer, sub-agent tagging, hooks forwarding and ctx.emit
• Docs: docs/compaction.md, docs/streaming.md, docs/configuration.md (+ api-overview note); llms-full.txt regenerated; CHANGELOG (Added)

How verified

• npx tsc --noEmit: pass
• npm run lint: 0 errors (404 warnings; none in the touched files)
• npm run test:types: 27 passed, no type errors
• npx vitest run: all pass after npm run build except cloudflare.test.ts "wrangler dev serves the worker" (needs the wrangler CLI/workerd, fails in isolation too, unrelated) and guardrails.test.ts child-kill timeout (flaky under load; passes in isolation, 23/23)
• npm run build && npm run build --workspace=packages/create-loushy-agent: pass
• npm run docs:verify-snippets -- --skip-build: all 116 snippets type-check; 6 also run
• npm run docs:llms:check: pass
• vitest run --coverage --config vitest.coverage.config.ts --exclude src/deploy/adapters/cloudflare.test.ts: 153 files, 2221 passed, 3 skipped; npm run fallow: exit 0, no dead code (one pre-existing duplicate block in AnthropicProvider/OpenAIProvider)

🤖 Generated with Claude Code

https://claude.ai/code/session_016bY29ibQgv3MDdjAbUT4YR

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