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

Annotations already declare the safe-read profile (readOnly, idempotent, non-destructive), but the description adds substantial context: no decision-unit debit, owner-approved scoped access required, 90-day expiry with RECORD_EXPIRED halt guidance, HTTP 429/Retry-After handling, and that no result grants external-action authority.

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-loads the purpose and is dense with uniquely useful clauses, so little is wasted. It is heavy on semicolon-chained constraints, which is slightly taxing to parse, but every sentence carries actionable content.

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, return values need not be explained, and the description still covers auth, expiry, error codes, rate-limit behavior, and the exact identity semantics of the two required parameters. Nothing an agent needs to call this 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%, so the baseline is 3, but the description goes further by clarifying that operation_id must be the original ID (not decision_id or record_hash) and that JSON key order is immaterial while values must be identical. This meaningfully reduces mis-invocation risk beyond the schema.

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?

States a specific verb (read) and resource (compact verdict/reason/policy/hash summary of an owned saved decision), and explicitly scopes what is excluded (receipt signature omitted). It names the sibling decide_prepaid_export_record for full signed evidence, so an agent can distinguish it without opening the schema.

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 says when to use it ('after decide_prepaid_evaluate, including lost replies') and names the alternative for a different need (export_record for full signed evidence). It also states the failure conditions to expect (Pending returns no record; missing references return RECORD_NOT_FOUND).

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