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

Annotations tell the agent this is a read-only, idempotent, non-destructive, open-world query. The description adds meaningful non-annotation context: the credit cost model, the preview truncation (up to 5 rows, 20 calls/day without a key), and the Blind Mode ingestion limit. It does not disclose pagination behavior beyond the default, but the pricing and Blind Mode disclosures carry real operational value.

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?

Three dense, front-loaded sentences with no filler. The content is information-rich, though the sentence combining source description, field list, Blind Mode, AND semantics, and pricing in one block could be split for scannability.

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 complex 16-parameter query tool with no output schema and no annotation coverage of parameters, the description is moderately complete: it covers data source, fields, pricing, and the Blind Mode caveat. But it leaves parameter behavior, pagination, and result shape unaddressed, which matters for such a broad filter surface.

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 description coverage is 0%, so the description must carry parameter semantics, but it only gestures at them ('filters combine with AND; q searches all text fields'). It does not explain the 16 parameters individually — CPV codes, notice_type, procedure_type, contract_nature, places_of_performance, and the date range params are all undocumented in both schema and description. This leaves significant gaps for a 16-param tool.

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 specifies a concrete verb and resource ('Contract notices and awards from TED'), names the data source (the official EU procurement journal), and enumerates the fields returned (buyer, country, CPV codes, values, deadlines). This makes it easy to distinguish from sibling tools like query_uk_tenders that cover a different jurisdiction.

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 implies usage through 'filters combine with AND' and the Blind Mode note, but provides no explicit when-to-use or when-not-to-use guidance relative to siblings. An agent has to infer that this is the EU-jurisdiction procurement tool vs. the UK-specific ones.

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