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

Annotations already declare the full safety profile (readOnlyHint, idempotentHint, non-destructive, closed-world), so the description is not obligated to cover that. It adds genuinely new context beyond annotations: the result includes a freshness timestamp and a live count of open tenders per source, which tells the agent the data is snapshot-like and time-sensitive rather than static.

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?

One sentence, front-loaded with the core action, and every clause adds distinct information (coverage set, per-source counts, freshness). No filler or restatement of the title.

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?

A zero-parameter, read-only catalogue call with no output schema is well served by a description that enumerates the returned fields, as this one does. Only minor gaps remain, such as result ordering or whether the list is exhaustive of all supported regions, neither of which is likely to change how the agent calls it.

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?

There are zero parameters, so there is nothing for the description to disambiguate; the baseline for a parameterless tool applies. The description instead spends its words on what the call returns, which is the more useful information here.

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 names a specific verb ("List") and a specific resource ("UK procurement sources Buzz Tender Alert covers"), and it goes further by listing the per-source attributes returned: open tender counts and last refresh time. Siblings get_tender and search_tenders operate on tenders rather than on the source catalogue, so the resource distinction is unambiguous even without an explicit cross-reference.

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 only implied: an agent can infer this is the discovery/coverage call you make before searching, but the description never states when to call it or points to search_tenders as the follow-up step. No exclusions or prerequisites are given.

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