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

No annotations are supplied, so the description carries the full behavioral burden. It discloses that the return is 'clean text' and that the call costs 1 credit, which is useful, but omits behavior on invalid paths, truncation (implied by maxChars), and whether the leading slash is required.

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?

A single front-loaded sentence plus a parenthetical cost note, with zero wasted words. The example path and credit cost both earn their 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 simple two-parameter fetch tool with no output schema, the description is adequate but leaves gaps: it doesn't explain what 'clean' means, how maxChars affects the return, or error behavior. Combined with the absence of annotations, more disclosure would help an agent invoke 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 100%, so the schema itself is the baseline for parameter meaning. The description adds a concrete path example (/vat-rates) that clarifies format, but leaves maxChars semantics (truncation? character count?) unexplained beyond the bare schema.

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 states a specific verb ('Clean text of') and resource ('a GOV.UK page') and gives a concrete example path (/vat-rates), which lets an agent distinguish this fetch-a-page tool from search-style siblings like govuk_search. It doesn't explicitly name the sibling alternative, so it falls short of a 5.

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?

'by path (e.g. /vat-rates)' weakly implies this is used when you already know a path, but there is no explicit when-to-use guidance, no when-not-to-use, and no reference to govuk_search as the alternative for discovering paths.

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