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

With no annotations, the description carries the full behavioral burden, and it usefully discloses a per-call cost of 1 credit. It does not disclose authorization requirements, whether the name search is exact or fuzzy, pagination behavior tied to the limit parameter, or the shape of results.

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 covering both modes plus the cost; there is no filler or redundancy to trim.

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 three-parameter lookup tool with no output schema, the description covers purpose, both search modes, and credit cost adequately. The remaining gaps, notably limit semantics and no-result behavior, are modest but real.

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 coverage is nominally 100%, but the schema descriptions are placeholders that merely restate the type, so the description is the only source of meaning. It clarifies the roles of postcode and name but says nothing about limit, which is left entirely undefined.

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 ("Find the MP for a postcode", "search current MPs and peers by name") and covers both operating modes. It is clearly distinguishable from the sibling tools (petitions, legislation, food alerts), though it does not explicitly contrast itself with any of them.

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 description implicitly pairs each input with a mode: postcode for MP lookup, name for searching MPs and peers. There is no guidance on when to prefer one mode, what happens if both are supplied or neither is given, or what to do when no match is found.

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