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

With only readOnlyHint=true in annotations, the description carries the real behavioral burden and does so richly: anonymous callers see counts/values/dates but supplier and incumbent names are withheld with a withheld_reason, links require an API key or sign-in, values are published amounts never converted, and computed_at states the freshness date. It even instructs the agent to relay the withholding sentence verbatim.

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 summary line, the USE THIS WHEN block, and the parameter guidance are front-loaded before the long return/visibility caveats, so the essential routing information is read first. The remaining prose is dense and mostly earns its place, though the coverage/attribution sentence is borderline boilerplate.

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?

Although an output schema exists, the description usefully names every returned array (expiring, planned, recent_awards, top_suppliers, open_tenders, computed_at, sources), discloses the anonymous-caller redaction, the link restriction, and AU/NZ source coverage. An agent has everything needed to call it and to explain the result accurately.

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 0%, so the description must compensate, and it does: it states that buyer is 'the organisation name as published' and that buyer_key comes 'from a tender's buyer, or a previous answer', which tells the agent where each value originates. It does not clarify whether the two are mutually exclusive or what happens if both are omitted.

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?

Opens with a specific verb+resource summary — 'What a buyer has awarded, what is ending, and what they plan' — that names the exact slice of data returned. It is clearly distinguishable from siblings like find_tenders and find_signals because it is scoped to a single organisation rather than a market-wide search.

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?

Gives an explicit trigger ('USE THIS WHEN someone asks about a specific buyer before a bid') followed by three concrete query phrasings that map directly to the returned arrays. It stops short of naming alternatives or a when-not condition, so an agent must infer when to prefer find_tenders or find_signals instead.

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