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

Annotations already cover safety and idempotency, and the description adds the decisive behavioral fact an agent cannot get from them: coverage is partial ("a handful of tenders") and grows only by publisher request. That directly prevents the classic error of reading an empty result as 'this tender's deadline is unchanged.' It also discloses what each record carries — observation start, last successful check, freshness.

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?

Four sentences, front-loaded with the scoping question and the return payload, with the practical caveat last. Slight redundancy in "observation start, last successful check and freshness," which partially overlap, but nothing is wasted overall.

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 zero-parameter, read-only tool with an output schema, the description supplies everything needed: what is returned, how current it is, why coverage is incomplete, and the interpretive caution. There is no missing prerequisite or side effect an agent would need to know before calling.

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 tool takes no parameters and the schema is empty, so there is nothing to disambiguate; baseline of 4 applies. The description correctly spends no words on phantom inputs and instead describes the shape of the returned records.

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?

Opens with a specific interrogative that names both the verb-like action (report which tenders are watched) and the resource (EU tenders with submission-deadline changes), then enumerates the return payload. An agent can immediately separate this from aurelmark_ted_changes, which presumably reports the changes themselves rather than the coverage list.

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?

"Use to find out whether a tender is covered before concluding anything about its deadline" gives an explicit precondition and a negative guardrail (don't infer deadline status without coverage). It stops short of naming aurelmark_ted_changes as the follow-up call once coverage is confirmed, so the routing is inferable but not spelled out.

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