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

The description adds behavioral context beyond the annotations by listing the exact returned fields (award value, lead organisation, etc.) and confirming it works with both GUID and human-readable references. This enriches the agent's understanding of what the tool does.

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 sentences, concise and front-loaded. The first sentence states the purpose and identifier formats, the second lists returns. No filler or redundancy.

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 lookup tool with one parameter and no output schema, the description adequately covers input and output. It mentions specific return fields, though it doesn't discuss pagination or error handling, which are minimal for this use case.

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 input schema already has 100% coverage with a detailed property description and examples. The description restates the parameter's purpose but does not add new semantic constraints or format details beyond what the schema provides.

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 explicitly states the tool returns full detail for one UKRI-funded project, using verb 'looked up' and specifying the resource. It distinguishes from sibling tools like gtr_search_projects by emphasizing it returns comprehensive information for a single project.

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 clearly indicates it is for retrieving full details of a specific project when you have a GtR GUID or grant reference. It doesn't explicitly state when not to use it, but the context of looking up by identifier implies it's for known projects.

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