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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses the hard cap of 5,000 indicators, the 1–7 day bounding window, a 10-minute cache, and that the call is public/no-auth while the underlying bundle requires a free API key. It also points to bundle_url for the data this tool deliberately omits.

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?

The opening sentence is well front-loaded, but the usefulness rationale is stated twice — 'feed freshness' in the first paragraph and 'gauge feed depth and freshness' in the third, plus a nearly identical closing example sentence. Roughly one paragraph of the five is redundant.

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?

There is no output schema, so the description carries the return-value burden and does so thoroughly: window counts, top families vs. list labels, source feeds, indicator-type breakdown, countries, and bundle_url. An agent knows exactly what it will get back and what it will not.

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?

With one parameter at 100% schema description coverage, the schema already carries the bounds and default, so the baseline applies. The description reinforces the 1–7 day window semantics and provides an example call (`{"days": 7}`), but adds no syntax or interpretation beyond that.

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 — a shape report over the most recent 5,000 indicators in the DugganUSA STIX 2.1 feed — and enumerates the outputs (counts, top families/labels, source feeds, type breakdown, countries). It clearly distinguishes itself from a full bundle download, though it never names or contrasts with the sibling tools (search, enrich-ioc, check-package).

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?

Gives concrete use cases: gauging feed depth/freshness, planning SIEM or blocklist ingestion budgets, spot-checking that a campaign is in the corpus, and using it *before* pulling the full bundle. It also sets a boundary (does not return the bundle), but stops short of saying when another tool would be the better choice.

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