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

Annotations already declare readOnly, idempotent, non-destructive behavior, and the description adds important context: 'This read does not start a run', default page size of 10 capped at 100, and a prompt-injection warning that returned prose/notes/excerpts are data, not instructions. It stops short of describing error behavior when both company_id and ticker are omitted or invalid.

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?

Front-loaded with the core purpose, then selection parameters, alternatives, pagination mechanics, and a safety note. It is dense and slightly run-on in places, but every sentence provides actionable information and nothing is wasted.

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 five-parameter read tool with no output schema, the description covers what is returned, how to select the company, how to page the timeline, the sibling alternative, and the injection-safety caveat. Minor gaps remain around run_id-only behavior and required-selector validation, preventing a 5.

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 0% schema description coverage, the description carries the full parameter burden and does well: it states company_id or ticker as the company selectors, run_id plus timeline_page/timeline_per_page for pinned timeline pages, and gives the default (10) and maximum (100) for page size. It is slightly ambiguous about what run_id does on its own and whether company_id/ticker are effectively required despite the empty required array.

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 verb and resource ('Read one company: Helmbeam intelligence') and enumerates the returned contents — timeline page, brief's latest version, version/note counts, guide changes, data changes. It is clearly distinguishable from list_research and the run-oriented siblings.

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?

Explicitly names list_research as the alternative for listing brief versions, notes and past runs, and states the condition for supplying run_id with timeline_page/timeline_per_page. It does not cover when to prefer search_companies or get_company_evidence, but the routing for this tool's main decision is clear.

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