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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint, so the safety profile is fully covered. The description adds a freshness nuance ('when each source was last checked (null when unknown)'), but since an output schema exists, most of the field detail is redundant with structured data. Value added is real but modest.

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?

A single sentence that front-loads the action ('List the procurement sources') and then enumerates the returned fields. No filler, no repetition 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?

For a zero-parameter, read-only catalog listing with an output schema and full annotation coverage, the description is essentially complete: purpose plus freshness semantics. The only missing piece is routing guidance relative to sibling list/search tools.

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 zero parameters, so there is nothing for the description to disambiguate and the baseline is 4. The description correctly avoids inventing parameter behavior and simply describes the result set.

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?

States a specific verb and resource: 'List the procurement sources behind published notices', with the returned attributes spelled out. It is clearly distinguishable from search_public_tenders or list_public_tender_changes, but it never explicitly contrasts itself with the sibling 'facets' or 'changes' tools, so it stops 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?

There is no when-to-use statement and no mention of alternatives such as get_public_tender_facets or search_public_tenders. The agent must infer that this is the catalog-enumeration call from the name alone. This matches the calibration case for 'no guidance'.

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