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

With no annotations supplied, the description carries the full behavioral burden, and it discloses the most important non-obvious trait: the tool returns a do_not_answer refusal when the fact is drifted or unverified rather than guessing. That is a genuine honesty contract an agent must plan around. It still omits permission requirements, error shapes beyond the refusal, and response format, which keeps it off a 5.

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?

Two short sentences, front-loaded with the action and followed immediately by the failure contract. No filler, no restatement of the title, nothing that fails to earn its place.

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 one-parameter read tool this is close, and the refusal outcome partially covers what an output schema would otherwise provide. But with no output schema and 0% parameter coverage, the description should still say where fact_id comes from and roughly what a successful response contains.

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% for the single required parameter fact_id, so the schema adds nothing beyond 'it's a string.' The description does not explain what a fact_id looks like, its format, or how to discover one via wageuk_list_facts. With one undocumented parameter, the description fails to compensate for the coverage gap.

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: 'Get one verified fact from the wageuk pack.' Combined with the singular 'one fact' and the sibling naming pattern (wageuk_list_facts, wageuk_changes), an agent can infer this is the single-record retrieval sibling. It stops short of naming the alternative explicitly.

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 by the tool name and the 'one fact' framing, and the refusal clause hints at when the tool will not serve a request. However, there is no explicit guidance on when to prefer this over wageuk_list_facts, nor on how or where to obtain a fact_id before calling.

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