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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds substantial context beyond them: newest-first ordering, stable ids, decoded award metadata, source links, and the two distinct behaviors of 'ask' (record answer vs. named-account plan with triggers, roles, angles, gaps). This is rich disclosure that annotations cannot supply.

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?

It is front-loaded with what the tool returns, then walks parameters in order, and every clause about the 'ask' modes earns its place. The main flaw is that the 'ask' sentence nearly duplicates the schema description of the same parameter, adding minor redundancy.

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?

With no output schema, the description carries the return-value burden and does so reasonably well, describing the timeline contents, source links, and the two 'ask' output shapes. A few details (e.g. pagination/limits on a potentially long timeline) are unaddressed, keeping it just short of complete.

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 coverage is 100%, so the baseline is 3, but the description adds real meaning beyond the schema: it explains that 'fact' returns a single stored fact and must be omitted for the full timeline, that 'since' adds a what_changed block, and that 'ask' drives two different response modes not visible in the schema.

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 states a specific verb+resource ('Every public registry event the archive holds for one company, newest first') and enumerates the included record types (ClinicalTrials.gov device trials, Breakthrough authorizations, HDE approvals). It is highly specific, but it never names or distinguishes itself from the many sibling signal/brief tools, so it falls short of the 5 criterion.

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?

It gives clear mode-selection guidance per parameter: pass 'fact' for one stored fact, omit it for the full timeline, pass 'since' to add what changed, pass 'ask' to answer a question. This is explicit usage context, though it offers no when-not-to-use or named alternative sibling tools.

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