lookup_postcode

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

Description implies a read operation with no side effects. But with no annotations, it does not detail rate limits, authentication, or exact output fields beyond 'metadata'. Acceptable for a simple lookup but could be more explicit.

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?

Single, focused sentence with no extraneous information. Perfectly concise for the tool's simplicity.

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?

Output schema exists, so return values are documented. However, the description could clarify what 'location/geography metadata' entails (e.g., lat/long, region). For a single-parameter lookup, it's adequate but leaves some ambiguity.

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?

The only parameter 'postcode' has no schema description (0% coverage). The description adds 'UK' context, specifying the geographical scope. However, no format or validation details are provided, so only minimal added value.

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?

Clearly states it looks up a UK postcode and returns location/geography metadata. Distinguishes from sibling tools like search_mp_by_postcode which is for MP lookup, and os_places_find_place which is a broader search.

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?

No guidance on when to use this tool versus alternatives like search_mp_by_postcode or os_places_find_place. Missing when-not-to-use context.

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