refactor(core): route title and compaction through shared model requests - #43555
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kitlangton
enabled auto-merge (squash)
August 20, 2026 03:19
# ------------------------ >8 ------------------------ # Do not modify or remove the line above. # Everything below it will be ignored. # # Conflicts: # packages/core/src/session/compaction.ts # packages/core/src/session/runner/llm.ts # packages/core/test/config/compaction.test.ts # packages/core/test/session-compaction.test.ts
kitlangton
disabled auto-merge
August 20, 2026 03:40
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What
Routes the two remaining hand-rolled session-scoped LLM request envelopes — title generation and compaction summaries — through the shared
SessionModelRequest.prepareboundary established in #42680. Callers keep policy (transcript selection, streaming, usage recording, event publishing); prepare owns all provider-visible shaping.Before / After
session/title.ts(title generation)titleagent's model (or session model fallback) viaSessionRunnerModel.resolvepreparescopeSessionModelHeaders.makemodel.requesthooksSessionModelHook.applytools: []Tool.Snapshot→ still[]on the wirewebSocketnever passed); hook middleware attached only when HTTP hooks are registered, matching the runnersession/compaction.ts(compaction summary)model/ref/costfieldsSessionRunnerModel.Resolvedcarried throughAutoInput/PlanSessionPromptCacheKey.make(session.id)— a forked session used its own idmodel.requesthookstools: []Tool.Snapshot→ still[]on the wirewebSocketnever passed); hook middleware attached only when HTTP hooks are registeredAudited and left alone
core/src/generate.ts(Generate.text) — a generic, non-session generate utility. It has no session scope: no session ID, no agent, no session headers, cache key, or hooks apply. Putting it behind a session-scoped boundary would invent scope it does not have, so it stays onLLMClient.generatedirectly.webSocket: "session"opt-in remains exclusive to the durable runner; neither title nor compaction passes it.Session context hooks stay away from title and compaction requests.
Unification must not change observable plugin behavior: title and compaction requests never ran
session.contexthooks before, so they still do not.preparegains acontextHooks: falseopt-out — context hooks shape the agent conversation, and title/compaction requests are not part of it, so their transcripts pass through unchanged — and both behaviors are pinned by tests ("keeps session context hooks away from title/compaction requests"). Conversation requests (runner,session.generate) keep running them.scope.toolsalso became optional: title and compaction requests carry no tools, and the empty snapshot now lives at the boundary that required it instead of duplicated at each call site.How
SessionTitleandSessionCompactionnow depend onSessionModelRequest.Serviceand build their requests withprepare({ scope, transcript }), dropping their private uses ofSessionModelHeaders,SessionModelHook,SessionModelHttp,SessionPromptCacheKey,PluginHooks, andApp.Tool.Snapshot;Prepared.executeToolis unused since neither site executes tools.SessionCompaction.AutoInput/Plancollapsemodel/ref/costinto oneSessionRunnerModel.Resolved; the runner'scompactionInputpassesloaded.modeldirectly.Prepared; policy stays in the callers.Scope
packages/core/src/session/title.tspackages/core/src/session/compaction.tspackages/core/src/session/runner/llm.ts(compaction input shape only)packages/core/test/session-title.test.ts,test/session-compaction.test.ts,test/config/compaction.test.ts(fixture shape + new coverage).changeset/unify-request-envelope.mdTesting
session.contexthook now reaches title requests; forked-session compaction asserts the fork root prompt cache key.bun typecheckandbun run testfrompackages/core: 1891 pass, 0 fail.