Memory Budget Provider Contract

Owner and Scope

Host runtime jbaruch/nanoclaw owns canonical memory counting and CommonMark section boundaries. Installed authority jbaruch/nanoclaw-host rules/memory-budget-policy.md covers its fixed image lookup and versioned metadata contract for the jbaruch/nanoclaw-admin memory-diet and memory-hygiene skills.

The runtime co-ships these reviewed artifacts in its host/agent images:

• container/shared/memory-budget-cli.mjs
• container/shared/memory-budget-policy.mjs
• container/shared/memory-budget-policy.json

The immutable agent copies live together under /app/shared/, owned by the image rather than the agent. The host uses the same source artifacts. The policy JSON is schema 1; parseMemoryBudgetPolicy owns its exact fields and bounds. No reader maintains a second heading list, budget threshold or Markdown parser.

Fixed Lookup and Input

• The admin reader invokes only node /app/shared/memory-budget-cli.mjs with no arguments.
• Caller data cannot select an executable, policy path, provider root or replacement parser.
• Supply the exact group MEMORY.md UTF-8 bytes on stdin, preserving BOM, CRLF and Unicode.
• The helper bounds input through the canonical policy's max_source_bytes before analysis.
• The helper reads only its co-shipped sibling policy/module and does not modify memory, references, policy or jobs.
• Before live use, verify the artifact and its parent cannot be written or renamed by the actual agent identity. A source fixture or copied writable helper is not deployed image evidence.

Output Schema 1

Exit 0 emits one JSON object and a newline, with these exact fields and no memory content:

Section names and exemption decisions come from the common host parser. Whole exempt sections stay verbatim in live memory, never become extraction/retirement selectors, and contribute only neutral growth metadata. Fences, quotes, lists and HTML do not become top-level selectors. Raw total size still includes exempt content.

An unavailable sibling, unsupported policy/version, oversized input, malformed UTF-8 or analyzer failure exits nonzero, emits no usable stdout and writes an actionable safe stderr diagnostic. Consumers discard partial/invalid output, report unknown budget as one validation issue, and preserve source memory. Never infer an empty exemption set or a clean budget from failure.

Memory Diet

The admin memory-diet skill runs only on an explicit main-group request. The main agent measures MEMORY.md with this helper, moves chosen incident sections verbatim into memory/incidents/ reference files, and leaves each heading with a one-line lesson and a link. Exempt sections are never chosen. The helper's metadata grants no memory-write authority; the owner's request does. The host's job-based extraction (plans, results, private journals) is retired.

Regression Coverage

• jbaruch/nanoclaw src/memory-budget-policy.test.ts: actual co-shipped CLI/module lookup, UTF-8/BOM/CRLF/scalar accounting, metadata-only stdout, missing/future siblings and invalid-input refusal.
• jbaruch/nanoclaw-admin tests/test_memory_hygiene.py: fixed command lookup, complete schema-1 output validation and unknown-budget refusal without source mutation.
• Native acceptance uses the composed actual-agent fixture and the rebuilt image; local fixtures do not replace that deployment check.