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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description goes well beyond that with non-obvious behavior: per-item credit cost, the 24h free replay rule with 409/422 failure codes, result ordering and the 'none is not proof of solvency' caveat. It stops short of stating rate limits or whether 'timeout' items are retried or billed.

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?

One dense paragraph, front-loaded with the core action and scope, then output shape, then cost, then the replay caveat. Every clause carries distinct information — no restatement of the title and no filler.

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 no output schema, the description supplies the return contract itself: up to 5 notices per item newest-first, latest_filing_date, and the four status values. Combined with cost and idempotency semantics, an agent has everything needed to call this correctly and interpret results.

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 already 100%, so the baseline is 3; the description still adds real meaning on top of the schema by noting that `siren` is an alias for `company_number` and that the identifier must be exact as printed on the notice. The idempotency_key semantics (same items, 24h window, 409 while running, 422 on mismatch) also clarify behavior the schema only hints at.

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 and resource ('Check ... counterparties for CORPORATE insolvency notices'), plus the batch scope ('up to 100', 'in ONE call') and the endpoint. The 'CORPORATE' qualifier and the bulk framing let an agent distinguish it from the single-entity insolvency_record / insolvency_search siblings without opening a 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?

Usage is implied rather than stated: the 'up to 100 ... in ONE call' phrasing signals when batching is appropriate, and the cost note ('every item costs 2 credits') offers an implicit efficiency argument. However, it never explicitly says when not to use this or names a sibling to use instead for a single lookup, and the idempotency note describes mechanics rather than selection criteria.

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