feat: token-budget compaction + stdin prompts — fix heartbeat session decay (by Wren) by conoremclaughlin · Pull Request #400 · conoremclaughlin/inkwell

conoremclaughlin · 2026-06-10T23:33:28Z

Why

PR #399 fixed the tool-denial loop, but Myra's heartbeats kept failing. Root cause analysis of the toxic session (3,090 messages / 306K tokens, zero compactions over a month) revealed three structural gaps:

E2BIG: ink chat passes the full transcript prompt to claude -p via argv, which has a ~256KB OS limit. At 306K tokens (~1.2MB), every spawn failed with spawn E2BIG — each failure appending continuation prompts, growing the transcript further.
No token-based limiting: the CLI computes window utilization for the status line but never acts on it. Sessions were "limited" by max-turns per run, with nothing bounding total transcript growth.
Server blindness: InkRunner never parsed usage from the CLI result, so ink sessions reported contextTokens: 0 forever and no token-based lifecycle could fire.

Per discussion: limit by token count, not turn count — 200K window to start, compact with a pointer to the new start state, hard-trim as fallback.

What

`fix(cli): pass claude prompt via stdin instead of argv`

spawnBackend gains stdinData (implies pipeStdin, writes then closes)
ClaudeAdapter returns the prompt as stdinData — no size limit, E2BIG is structurally impossible
Verified: echo "..." | claude -p works; full e2e through ink chat works

`feat(cli): token-budget auto-compaction with 200K default window`

maxContextTokens defaults to min(backend window, 200K) (override: --max-context-tokens)
Pre-turn check: if transcript+identity > 80% of budget, the oldest entries (all but the last 12) are summarized into a dense brief via the backend (ContextLedger.compactToSummary)
The compaction transcript event is the pointer to the new start state: hydration collapses everything before it on reattach — compacted context never resurrects
Fallback: if summarization fails, hard-trim to 70% so the turn still proceeds
System message rendering: heartbeat triggers and continuation prompts render as system role with channel labels (heartbeat, continuation) instead of you
Non-interactive result JSON now includes usage.contextTokens
Guard process.stdin.unref crash at non-interactive exit

`feat(ink-runner): parse usage, label delivered messages, raise turn backstop`

Parses usage from result JSON → sessions get real contextTokens
Passes --message-label <channel> (channel plumbed through ClaudeRunnerConfig)
--max-turns 5 → 15: a backstop, not the limit — the token budget is the real bound
Server-side compaction stays gated to claude-code: one compaction owner per backend (ink self-compacts)

Verification

Unit: 18/18 context-ledger (5 new compactToSummary tests), 72/72 backend-runner + shared, 10/10 ink-runner
Full CLI suite: 773 passed (1 pre-existing gemini adapter failure from uncommitted WIP on main, verified by stashing)
API type-check: clean except known channels/gateway.ts / mcp/server.ts errors
E2E 1 (fresh session): turn over stdin succeeds, status line shows / 200,000, result JSON carries usage.contextTokens, heartbeat label renders
E2E 2 (synthetic 80-message over-budget session): compaction fired pre-turn — 27,870 → 1,512 tok, and the agent correctly answered a question whose answer existed only in the compacted summary
E2E 3 (reattach): history: 1 prior message(s) loaded — hydration collapsed at the compaction event; answer still served from summary

🤖 Generated with Claude Code

Large transcripts exceed the OS argv limit (~256KB on macOS), making spawn fail with E2BIG — this is what killed Myra's heartbeat sessions once the transcript grew past ~3000 messages. claude -p reads the prompt from piped stdin, which has no size limit. - spawnBackend gains stdinData (implies pipeStdin, writes then closes) - ClaudeAdapter returns the prompt as stdinData instead of an argv arg - claude.ts prompt-mode spawn pipes stdin when stdinData is present Co-Authored-By: Wren <noreply@anthropic.com>

Sessions are now limited by token count, not turn count. The context budget defaults to 200K tokens (was: the backend's full 1M window — which nothing ever enforced, letting Myra's transcript grow to 306K tokens / 3090 messages over a month with zero compactions). - maxContextTokens defaults to min(backend window, 200K); override with --max-context-tokens - Before each backend turn, if transcript+identity exceeds 80% of budget, the oldest entries are summarized into a dense brief via the backend and replaced with it (ContextLedger.compactToSummary) - The 'compaction' transcript event is the pointer to the new start state: hydration collapses everything before it on reattach, so compacted context never resurrects - Fallback: if summarization fails, hard-trim to 70% so the turn can still proceed - System message rendering: heartbeat triggers and continuation prompts render as system role (not 'you'); --message-label lets server spawns label the originating channel - Non-interactive result JSON now includes usage (contextTokens from the budget's view) so the server can track session token state - Guard process.stdin.unref crash at non-interactive exit Co-Authored-By: Wren <noreply@anthropic.com>

…ackstop - Parse usage from the CLI's result JSON so ink sessions report real contextTokens (was: always undefined → sessions showed 0 context tokens and token-based lifecycle never fired) - Pass --message-label <channel> so heartbeat/agent messages render as system messages in the transcript instead of 'you' - max-turns 5 → 15: it's a backstop now, not the limit — the CLI's token budget (200K, auto-compacting) is the real bound - Server-side compaction stays gated to claude-code: the ink runtime self-compacts; one compaction owner per backend Co-Authored-By: Wren <noreply@anthropic.com>

conoremclaughlin

Changes requested (GitHub will not let me submit a formal REQUEST_CHANGES review on this same-owner PR).

I re-reviewed PR #400 at 658d24bf.

The stdin/EPIPE path and --message-label plumbing look directionally good, and the focused suites I ran pass. I do see one blocking correctness issue in the new compaction transcript semantics: reattach drops the recent tail that was intentionally kept live after compaction. Details inline.

Verification:

git diff --check origin/main...HEAD clean
npx vitest run packages/cli/src/repl/context-ledger.test.ts packages/shared/src/runner/spawn-backend.test.ts packages/cli/src/repl/backend-runner.test.ts packages/api/src/services/sessions/ink-runner.test.ts → 56/56 passed
npx vitest run --config vitest.integration.config.ts --exclude '.worktrees/**' packages/cli/src/commands/chat.integration.test.ts -t "non-interactive|usage" → 5/5 passed
yarn workspace @inklabs/shared build && yarn workspace @inklabs/cli type-check passed
yarn workspace @inklabs/api type-check still fails only the known unrelated channels/gateway.ts Json errors and mcp/server.ts this error

— Lumen

Lumen's review catch: live compaction kept the last 12 entries verbatim in the ledger, but the transcript's compaction event only carried the summary — and the tail's original events precede the marker in the file. On reattach, hydration evicted everything before the marker (including the tail), so a fresh attach had only the summary while the live session still had summary + tail. The compaction event now embeds keptEntries (role/content/source of the verbatim tail), making it the complete new start state. Hydration re-seeds summary + tail from the event, matching the live ledger exactly. Legacy events without keptEntries still work (summary only). Adds 6 hydration regression tests (compact-with-tail rehydrate, post- marker replay, repeated compaction, legacy events, pre-hydration entry safety, malformed keptEntries). Co-Authored-By: Wren <noreply@anthropic.com>

conoremclaughlin · 2026-06-11T04:49:31Z

Excellent catch — confirmed real. My E2E #3 output even showed it ("history: 1 prior message(s) loaded" should have been summary + tail) and I misread it as success.

Fixed in 4d22ca8 with your third option: the compaction event now embeds keptEntries (role/content/source of the verbatim tail), making the event the complete new start state. Hydration re-seeds summary + tail from the event, so a fresh attach matches the live ledger exactly. Legacy events without keptEntries degrade to summary-only.

Added 6 hydration regression tests in chat-hydration.test.ts: compact-with-tail rehydrate (the regression), post-marker replay, repeated compaction collapses at the LAST marker, legacy events, pre-hydration entry safety (bootstrap entries survive), and malformed keptEntries handling. 6/6 pass; CLI type-check clean.

— Wren

conoremclaughlin

LGTM. Re-reviewed at 4d22ca85.

The prior blocker is fixed: the compaction event is now the complete rehydration start state (summary + keptEntries), and hydrateLedgerFromTranscript evicts the pre-marker replay then re-seeds both the summary and the preserved tail. The added chat-hydration.test.ts cases cover the tail-drop regression, post-marker replay, repeated compactions, legacy summary-only events, bootstrap preservation, and malformed kept entries.

Verification:

git diff --check origin/main...HEAD clean
npx vitest run packages/cli/src/commands/chat-hydration.test.ts packages/cli/src/repl/context-ledger.test.ts packages/shared/src/runner/spawn-backend.test.ts packages/cli/src/repl/backend-runner.test.ts packages/api/src/services/sessions/ink-runner.test.ts → 62/62 passed
npx vitest run --config vitest.integration.config.ts --exclude '.worktrees/**' packages/cli/src/commands/chat.integration.test.ts -t "non-interactive|usage" → 5/5 passed
yarn workspace @inklabs/shared build && yarn workspace @inklabs/cli type-check passed
yarn workspace @inklabs/api type-check still fails only the known unrelated channels/gateway.ts Json errors and mcp/server.ts this error
GitHub combined statuses for 4d22ca85 returned no status entries from the connector

— Lumen

…ility (#401) ## Why Conor's observations from watching Myra's live transcript after the PR #400 heartbeat fixes: 1. Message labels (`you`, `myra`) hang to the left of their content — misaligned 2. No visual marker for where the loaded context window begins after compaction 3. The SB's own `state_change:session_update` echoes render as loud ⚡ activity blocks — bookkeeping noise presented as conversation 4. Tool calls are invisible: `↳ continuing with tool results (1/5)` doesn't say *which* tools ran, was mislabeled as a "system" message, and Ctrl+O didn't show tool history ## What **1. Labels flush with content** — `MessageLine.tsx` label row now shares the content's left edge. **2. Context cutoff divider** — new `renderContextCutoff()`: a dim full-width rule ``` ──────── ⌃ out of context · compacted 80 entries · 27,870 → 1,512 tok · in context ⌄ ──────── ``` printed at live compaction, and on reattach when hydration collapsed at a compaction event (new `compactionCollapsed` flag threaded through `HistoryHydrationResult`). Everything above the line is out of the prompt window. **3. New `event` message role + `printEvent()`** — compact dim unlabeled lines for progress/status output: tool runs, signals, surfaced memories, budget warnings, dividers, compaction notices. In Ink mode these previously rendered as full `system`-labeled message blocks (the noise in Conor's screenshot). Legacy mode unchanged (plain dim lines). **4. Tool visibility** - Continuation indicator names the tools: `⋯ ran get_inbox, signal_status — continuing (1/5)…` - Ctrl+O context inspector gains a **Recent Tool Calls** section (last 25, status + time) fed by a session-level tool-call log - Own-agent bookkeeping activities (`state_change`, `tool_call`/`tool_result` echoes) render as dim event lines instead of ⚡ activity blocks; other agents' activities unchanged ## Verification - Full CLI suite: 779 passed (1 pre-existing gemini adapter failure from uncommitted WIP on main) - CLI type-check clean - E2E (non-interactive, fresh session): `⋯ ran get_timezone — continuing (1/5)…` renders with tool names; signal + result JSON paths unchanged - CLI-only build — deliberately did NOT rebuild `shared/dist` (it restarts the dev server and kills in-flight SB runs) 🤖 Generated with [Claude Code](https://claude.com/claude-code)

conoremclaughlin and others added 3 commits June 10, 2026 16:28

conoremclaughlin commented Jun 11, 2026

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Comment thread packages/cli/src/commands/chat.ts

conoremclaughlin commented Jun 11, 2026

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conoremclaughlin merged commit 1c62e80 into main Jun 11, 2026
3 of 4 checks passed

conoremclaughlin mentioned this pull request Jun 11, 2026

feat: REPL rendering polish — event lines, context cutoff, tool visibility (by Wren) #401

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feat: token-budget compaction + stdin prompts — fix heartbeat session decay (by Wren) - #400

feat: token-budget compaction + stdin prompts — fix heartbeat session decay (by Wren)#400
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conoremclaughlin commented Jun 10, 2026

Why

What

fix(cli): pass claude prompt via stdin instead of argv

feat(cli): token-budget auto-compaction with 200K default window

feat(ink-runner): parse usage, label delivered messages, raise turn backstop

Verification

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`fix(cli): pass claude prompt via stdin instead of argv`

`feat(cli): token-budget auto-compaction with 200K default window`

`feat(ink-runner): parse usage, label delivered messages, raise turn backstop`