feat(server): enforce configurable thread context limits

[saphid]

Summary

Long threads resend their whole conversation on every turn, so a thread that keeps growing quietly burns provider quota. T3 had no way to stop that.

This adds a per-environment threadContextTokenLimit server setting — default 250,000 tokens, adjustable 50,000–1,000,000 in Settings → General (searchable as "Thread token limit"). Before a turn starts provider work, the server checks the thread's latest reported context usage; at or over the limit it records a failure activity explaining the usage and the configured limit instead of starting the provider.

• Enforcement runs on the server's turn-start path, so it covers web, desktop, and mobile turns alike (mobile has no settings screen for it; the environment-level limit still applies).
• /compact bypasses the gate so an over-limit thread can always compact its way back under the limit.
• Messages sent while compaction runs are queued as before, then re-checked when the compaction queue replays them — a replayed turn is rejected if the thread is still over the limit, rather than silently bypassing.
• Only providers that report context usage are enforced; providers that never report it are not limited (documented in docs/user/usage.md).
• The admission read is activity-only (includeMessages: false on the detail query), so gating does not hydrate conversation message bodies.
• With multiple environments selected and differing limits, the row renders the standard "Mixed" state instead of the representative environment's value; committing a value still fans out to every selected target.

Verification

• vp test run on touched scopes: ProviderCommandReactor.test.ts 75 passed, UsageLimitPolicy.test.ts 5 passed, settings.test.ts 130 passed. Covers below/at/above the threshold, /compact bypass with queued messages, replayed turns re-gated after compaction (accepted under, rejected over), and schema defaults/bounds.
• vp run typecheck on apps/server, apps/web, packages/contracts — clean (pre-existing effect-tsgo suggestions only).
• Focused lint on touched files — 0 errors. vp fmt clean.
• Rebased onto current origin/main; adopts the scoped-server-settings and queue/steer conventions that landed since this branch was cut.

Media

Captured on an earlier revision of this branch in the real app; the settings row now also shows the standard value-source indicator and its description says reported context, but the behavior shown is unchanged.

Before — no limit setting:

After — the row in Settings → General:

Over-limit turn blocked:

/compact recovers:

Clean MP4s: before · after · blocked · recovery

Coordination trace: T3 thread 49da953a-5d94-48cb-8c1f-c4a2d90bd340

Model: SWE-2 Max via T3 Code

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR adds a default-on server admission gate that can stop provider turns when reported thread context reaches 250,000 tokens, along with a new environment setting and compaction recovery flow. Because it changes the product default and materially changes existing runtime behavior, the change warrants human review.

^{You can add or adjust custom eligibility rules. Learn more.}

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📥 Commits

Reviewing files that changed from the base of the PR and between 184d8c8 and 720b0aa.

📒 Files selected for processing (11)

• apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.ts
• apps/server/src/orchestration/Layers/ProviderCommandReactor.test.ts
• apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
• apps/server/src/orchestration/Services/ProjectionSnapshotQuery.ts
• apps/server/src/orchestration/UsageLimitPolicy.test.ts
• apps/server/src/orchestration/UsageLimitPolicy.ts
• apps/web/src/components/settings/SettingsPanels.tsx
• apps/web/src/components/settings/settingsSearch.ts
• docs/user/usage.md
• packages/contracts/src/settings.test.ts
• packages/contracts/src/settings.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• docs/user/usage.md

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---

📝 Walkthrough

Walkthrough

Adds a configurable server thread context token limit. The server evaluates persisted context usage before provider turns, permits compaction turns, and omits message loading for activity-only reads. The web settings and usage documentation expose the limit.

Changes

Thread context limits

Layer / File(s)	Summary
Limit contract and settings packages/contracts/src/settings.ts, packages/contracts/src/settings.test.ts, apps/web/src/components/settings/SettingsPanels.tsx, apps/web/src/components/settings/settingsSearch.ts, docs/user/usage.md	Defines 50,000–1,000,000 token bounds with a 250,000-token default. Adds patch validation, General settings controls, search terms, and usage documentation.
Context limit evaluation apps/server/src/orchestration/UsageLimitPolicy.ts, apps/server/src/orchestration/UsageLimitPolicy.test.ts, apps/server/src/orchestration/Services/ProjectionSnapshotQuery.ts, apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.ts	Evaluates the latest context snapshot or post-compaction usage. Adds tests for configured limits and compaction behavior. Allows raw detail reads to omit messages.
Provider turn admission apps/server/src/orchestration/Layers/ProviderCommandReactor.ts, apps/server/src/orchestration/Layers/ProviderCommandReactor.test.ts	Checks context usage before standard provider work, records limit failures, and bypasses the check for authentication and compaction-related turns. Tests threshold, recovery after compaction, and queued replay behavior.

Priority: ➖ Normal

Estimated code review effort: 4 (Complex) | ~45 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant Client
  participant ProviderCommandReactor
  participant ProjectionSnapshotQuery
  participant UsageLimitPolicy
  participant Provider
  Client->>ProviderCommandReactor: Request provider turn
  ProviderCommandReactor->>ProjectionSnapshotQuery: Load context activities
  ProjectionSnapshotQuery-->>ProviderCommandReactor: Return thread detail
  ProviderCommandReactor->>UsageLimitPolicy: Evaluate context usage
  UsageLimitPolicy-->>ProviderCommandReactor: Return admission result
  ProviderCommandReactor->>Provider: Call sendTurn when admitted

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Suggested reviewers: juliusmarminge, t3dotgg

Merge Risk: ⚪ Minimal · up to 720b0

The context-limit gate, compaction recovery path, and documentation behavior are covered by the current changes; no merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 6 functions across 10 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the main change: configurable server-side thread context limits.
Description check	✅ Passed	The description clearly explains the change, motivation, behavior, UI impact, verification, and media evidence. It uses Summary, Verification, and Media headings instead of the template's What Changed…

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 6 functions across 10 files. (1 skipped: 1 unsupported.)

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[saphid]

Independent automated first-pass review (Amp/Astra, no file modifications): 3 findings.

Addressed (61374dc): admission gate blocked /compact, so an over-limit thread had no compaction recovery path — compact commands now bypass the gate, with a test.

Dismissed: (1) providers without thread.token-usage.updated (Cursor/Grok/Antigravity/OpenCode) never enforce the limit — real gap but a foundation-scope decision, not a bug in this patch; better as a follow-up. (2) admission reuses getThreadDetailById which still loads plans/checkpoints — bounded turn-start-only query, acceptable perf trade; also follow-up material.

[saphid]

Friendly review nudge @juliusmarminge @maria-rcks — this is mergeable and hasn't had a maintainer pass yet. Independent bot/agent reviews have run with findings triaged in-commit (see receipts in earlier comments). Full queue context and status: #10688.

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[coderabbitai]

Actionable comments posted: 2

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Inline comments:
In `@apps/server/src/orchestration/Layers/ProviderCommandReactor.ts`:
- Around line 1298-1302: Update the bypassesContextLimit calculation in the turn
handling flow so resumed/replayed turns do not bypass evaluateTurnStartLimits;
retain the bypass for the original event that enters the queue, along with the
existing compact-command and compaction-tracking conditions. Ensure replayed
turns are checked before reaching sendTurn.

In `@docs/user/usage.md`:
- Around line 71-72: Update the usage-limit documentation near the Settings →
General guidance to state that enforcement applies only when the provider
reports thread context usage via thread.token-usage.updated; do not claim the
limit applies to every provider or client.

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📥 Commits

Reviewing files that changed from the base of the PR and between 61374dc and 184d8c8.

📒 Files selected for processing (9)

• apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.ts
• apps/server/src/orchestration/Layers/ProviderCommandReactor.test.ts
• apps/server/src/orchestration/Layers/ProviderCommandReactor.ts
• apps/server/src/orchestration/UsageLimitPolicy.ts
• apps/web/src/components/settings/SettingsPanels.tsx
• apps/web/src/components/settings/settingsSearch.ts
• docs/user/usage.md
• packages/contracts/src/settings.test.ts
• packages/contracts/src/settings.ts

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[saphid]

Rebased onto current main and pushed 8ce42859. What changed in this revision:

• Replayed queued turns re-evaluate the limit. resumed !== undefined no longer bypasses the gate — only /compact and messages that first arrive while compaction is running (or already queued behind it) skip it at entry. When the compaction queue replays them, they re-check against the post-compaction afterTokens value and are rejected if still over the limit. (coderabbit + macroscope findings)
• Mixed multi-environment state. The new row reads useScopedSettingsMixed — with differing per-environment limits it shows the standard "Mixed" placeholder instead of the representative environment's value. (macroscope finding)
• Docs. docs/user/usage.md states the limit relies on provider-reported context usage; providers that never report it are not limited. (coderabbit finding)
• Adopted current conventions: settingKeys value-source indicator, environment-only scope in the settings search catalog.

Verification: ProviderCommandReactor.test.ts 75 passed + UsageLimitPolicy.test.ts 5 passed; settings.test.ts 130 passed; typecheck clean on apps/server, apps/web, packages/contracts; focused lint 0 errors.

[macroscopeapp]

All clear

^{Posted via Macroscope — Effect Service Conventions}

[macroscopeapp]

All clear

^{Posted via Macroscope — Effect Service Conventions}

[juliusmarminge]

Thanks for the PR. We're not taking changes to the orchestration and provider layers right now: that part of the server is being rewritten for V2, and merging into the current code would either conflict with or be thrown away by that work.

Closing for now. If this is still an issue once V2 lands, please reopen (or open a fresh PR against the new code) and we'll take a proper look.