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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, so the safety profile is covered. The description adds meaningful behavioral context beyond annotations: it states coverage ('roughly 2,400 records'), scope ('all Commission-funded work delivered in partner countries'), and enumerates the returned fields (reference, title, budget, deadline, status, zone, URL). This adds value without contradictions.

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 three sentences, but they are information-dense and well-structured. The first sentence establishes the core purpose, the second provides examples, and the third distinguishes from TED. Each sentence earns its place, though the first sentence 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?

With no output schema, the description appropriately explains the return values ('Returns the reference, title, contract budget and currency, submission deadline, status word, geographical zone and portal URL'). It also covers the data domain and scope, and the TED distinction. Minor gaps exist around pagination behavior and status semantics, but those are partially covered by the schema.

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 100%, so the baseline is 3. The description's example queries ('what EuropeAid contracts are open in Nigeria') illustrate usage but do not add new meaning to the parameters beyond what the schema already provides. The status enum is already explained in the schema, and no additional constraints are documented.

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 uses a specific verb ('Search') and resource ('EuropeAid external-action contracts'), then further specifies 'the European Commission's own development cooperation, humanitarian aid and technical assistance tenders'. It also provides concrete example queries and distinguishes itself from TED, making the tool's purpose unmistakable.

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 explicitly states a clear alternative and exclusion: 'For a contract notice published by a national or municipal buyer inside the EU, that is TED... a separate and far larger journal.' It also gives example queries, implying when to use. However, it does not contrast with other sibling tools like eu_open_calls or eu_search_calls, leaving some ambiguity among the EU-related siblings.

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