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

Annotations already declare the tool as read-only, idempotent, and non-destructive. The description adds significant behavioral detail beyond annotations: it specifies the exact data returned (expected-outcome, scope, conditions, budget, types of action, deadline, etc.) and mentions that text is tag-stripped. It also maps tool outputs to user intents like 'what does this fund'.

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?

The description is clear and informative, but somewhat verbose with a long enumeration and two example questions. It is well-structured and front-loaded with the core purpose, but could be slightly more concise.

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?

Despite no output schema, the description comprehensively lists all return fields and gives example questions the tool answers. It fully compensates for the lack of output schema and leaves no ambiguity about what the tool returns.

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 has 100% description coverage for both parameters. The description adds the same example identifier and default behavior for include_conditions, but no additional meaning beyond the schema. Baseline 3 is appropriate.

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 EU funding call topic by its identifier', provides a concrete example identifier, and lists all fields returned. It clearly distinguishes from sibling tools like eu_search_calls and eu_open_calls which are for listing/searching.

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 when to use: when you have a specific topic identifier and need full details. It does not explicitly mention alternative tools for searching, but given sibling tool names, an agent can infer. Slight lack of explicit exclusions.

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