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

With no annotations, the description itself must disclose behavior. 'Search' implies a read-only operation and the scope is clear, but there is no mention of result shape, pagination, or limits beyond the schema's default/max. These are useful behavioral details the agent would have to discover elsewhere.

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, front-loaded with the core scope and followed by the query dimensions. Every word earns its place and no unnecessary detail is included.

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 search tool with five optional parameters, all fully described in the schema, the description is nearly complete. The main gap is the absence of an output schema or any statement about what fields the returned opportunities contain.

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 provides 100% description coverage for all five parameters, so the description adds little meaning beyond what the schema already offers. The brief mention of query dimensions mirrors the existing parameter descriptions.

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 a specific action ('Search') and a well-defined resource ('open European funding opportunities, Horizon Europe calls, national grants, and public tenders across 31 countries'). It also lists the dimensions by which to search, making the tool's role clear and distinct from detail/award retrieval.

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 gives a clear context for using the tool: discovering open funding across countries and categories. It does not explicitly contrast with get_grant_details or get_contract_awards, but the search-oriented wording makes the selection fairly obvious.

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