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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is fully covered without description help. The description adds the useful out-of-band caveat that ACTIVE scope does not guarantee an open bid deadline, and notes that results carry TED source URLs, but it repeats the schema's own scope wording and says nothing about pagination, result caps behavior, or failure modes.

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 action and filters, then the caveat. Dense and free of padding, though the parenthetical enumerations read slightly like a schema echo rather than added information.

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 five-parameter, all-optional read tool with full schema coverage and no output schema, the definition is close to complete: it names the data source, the filter set, and gives a hint about returned content (TED source URLs). What remains unstated is result volume/shape beyond that single field and whether defaults make the tool usable with zero arguments.

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 100%, so every one of the five parameters is already documented with patterns, defaults, and ranges. The description merely restates those parameters in list form and adds no syntax, format, or interaction semantics beyond the schema, making the baseline 3 correct.

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 opens with a specific verb+resource ("Search official European TED procurement notices") and enumerates the exact filter dimensions (buyer country ISO-3, CPV, days, limit). It does not need sibling differentiation because no sibling tools exist, which keeps it just short of a 5.

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?

Usage is implied rather than stated: the parameter list tells the agent what can be filtered, but there is no explicit "use this when..." framing or guidance on how the filters interact (e.g. whether country is effectively required in practice despite being optional with a ROU default). The read-only / ACTIVE caveat is the only conditional guidance offered.

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