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

Annotations declare readOnlyHint=false and openWorldHint=false, so safety characteristics are already partly covered. The description adds the useful cost trait ('Free') and clarifies the comparison scope (retained vs. latest preserved state). It does not disclose whether the call can mutate anything despite readOnlyHint=false, which is a notable omission for a get-prefixed tool.

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 sentence, front-loaded with the usage trigger, with no filler. It is appropriately sized, though the terse phrasing leaves the purpose statement implicit rather than stated outright.

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-value explanation is not required. But the description is silent on how to obtain a valid source_id and on how this tool relates to check_guidance_status, which are the two things an agent most needs to call it correctly.

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% and the single parameter 'source_id' has no title or description in the schema. The description never mentions source_id, how to obtain it, or its format, so it fails to compensate for the coverage gap. A sibling like list_guidance_sources would presumably supply valid IDs, but no link is made.

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 description names the specific resource (monitored official UK employment guidance) and the specific question it answers (whether/what changed, and whether earlier retained guidance differs from the latest preserved state). It is clear about what is returned, though it never states a verb like 'returns' and does not differentiate itself from the close sibling check_guidance_status.

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?

It gives an explicit trigger condition: 'Use when the task asks whether... guidance changed, what changed, or whether earlier retained guidance differs.' That is a clear when-to-use signal. However, it names no alternatives or exclusions, so the agent must guess how this differs from check_guidance_status or get_verification_evidence.

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