Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and largely does so: it discloses the mutating nature ('writable, not read-only'), a rate limit with the failure code (≤60/hour/key → 429), PII scrubbing of phones/emails in the note, key-based scoping via x-temsor-pbx-key, and cost behavior (idle $0, no LLM/PSTN). It stops short of naming auth requirements or whether a close is reversible, though the sibling pbx_promises_reopen implies recoverability.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the action, then operational facts (rate limit, scrubbing, scoping, cost) in compact form with no filler. The telegraphed shorthand is dense but every sentence carries information; only the demo-oriented remark borders on padding.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation tool with no annotations and no output schema, this covers the important operational surface: rate limits, failure code, privacy handling, key scoping, and cost. It would be a 5 with an explicit note on openness preconditions or reversibility, but nothing critical for a correct call is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents promise_id, status, and note; the description merely restates them as 'POST /v1/pbx/promises/close {promise_id, status:kept|broken, note?}'. It adds no format, constraint, or syntax detail beyond the schema, which is the expected baseline when coverage is complete.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb and resource: 'Mark an open promise kept or broken with an optional privacy-safe note.' The closing action and its two outcomes are unambiguous, and 'promises' distinguishes it from unrelated siblings like pbx_calls or pbx_redact. It does not explicitly contrast with pbx_promises_reopen or pbx_promises_act, so differentiation is partial.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied rather than stated: the tool closes 'an open promise,' which scopes it to opened promises only. No explicit when-to-use vs pbx_promises_act/pbx_promises_reopen guidance, and no stated preconditions (e.g., that the promise must currently be open).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.