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

Annotations declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, yet the description presents the tool purely as a lookup and never mentions whatever non-read-only behavior the hint signals. It does add one behavior not in the annotations ('Free'), giving cost transparency, and its 'bounded GOV.UK source set' wording is consistent with openWorldHint=false. Net: useful cost disclosure, but silent on the side-effect profile an agent needs.

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 compact sentences with the usage trigger front-loaded, and the terse 'Free.' earns its place by disclosing cost. Nothing is padded. The density of unresolved jargon ('G05', 'monitored source') costs it the top mark.

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?

An output schema exists, so return values need not be described, and the single-parameter surface keeps the burden low. The description covers trigger, scope and cost. What is missing is differentiation from list_guidance_sources/get_guidance_changes and any hint about the non-read-only behavior flagged by annotations.

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 'query' parameter, so the description must carry the semantic load. It partially does so by implying the query is plain employment/payroll language to be mapped rather than exact codes, which is real information about input form. It gives no syntax, format, or example, so it does not fully 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?

The second sentence gives a concrete verb+resource+scope: 'Searches only the bounded GOV.UK source set', which tells an agent this queries guidance content rather than enumerating it. The framing sentence adds that the function is mapping everyday employment/payroll wording onto a monitored 'G05' source. It stops short of explicitly distinguishing itself from the sibling list_guidance_sources, and 'G05' is never unpacked, so it is clear but not fully self-differentiating.

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?

The opening clause states a specific trigger ('Use when ordinary employment/payroll language must be mapped to a monitored G05 source before checking current official guidance'), including a sequencing instruction that this precedes consulting official guidance. That is strong when-to-use guidance. It names no alternative tool and gives no when-not condition, so it does not reach a 5.

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