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

Annotations declare readOnlyHint, idempotentHint, openWorldHint=false, and the description is consistent with all of them while adding meaningfully beyond them: it discloses that the operation is 'unmetered against your corpus allowance' and spells out the non-obvious account-wide scoping across re-mints and both auth methods. This is precisely the kind of behavioral context structured annotations cannot carry.

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?

The core statement is front-loaded and the paragraphs are logically ordered (what → value → usage → scope → parameter). The scope discussion is somewhat verbose, but every sentence carries non-obvious, operationally important information (account-scoping, re-mints, credential unification, the exceptional hand-minted case) that an agent would otherwise misuse the tool without. Slightly long, justified by complexity.

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?

With an output schema present to document return values, the description covers everything else an agent needs: purpose, failure-diagnosis value, account-level scope semantics, scope limits, exceptions, limit constraints, read-only safety, and metering behavior. Nothing an agent requires to invoke it correctly 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 coverage is 100% with a single `limit` parameter (1-500, newest first). The description restates this ('`limit` is 1-500, newest first') but adds little beyond the schema's own description. Per the baseline rule for high schema coverage, a 3 is appropriate — the schema does the heavy lifting and the description merely reinforces it.

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?

The description opens with a precise verb+resource statement — 'What this token has called, newest first — the log of your own use' — which unambiguously identifies the tool as an audit log of API calls. It goes further and differentiates from siblings by explaining what the tool is NOT (caps), pointing to get_plan for that purpose. The refusal-log emphasis ('why did my agent stop') gives a distinctive identity no sibling shares.

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?

Explicitly frames when to use it: 'to see what your agent actually did, to find the call that failed, or to check how much of today's caps you have spent.' It names the alternative for caps (get_plan) and describes the scope exclusions ('no argument that widens it beyond your own account, and none that narrows it'). The hand-minted-token exception is also called out, leaving no ambiguity about applicability.

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