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

Annotations already declare readOnly, idempotent, non-destructive behavior, lowering the bar. The description adds genuine context beyond them: 'FREE beta' flags pricing/maturity and 'compact latest observations' discloses the return shape (summarized, most-recent-only). It still omits rate limits, auth requirements, and error behavior.

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?

Two short sentences with zero filler and the 'FREE beta' caveat front-loaded. It is efficient, though the extreme brevity leaves gaps that a slightly longer description could close.

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 should carry return-value detail, but 'compact latest observations' is the only hint about what comes back. It also leaves the required 'cik' parameter unexplained and gives no sizing, pagination, or versioning guidance.

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 only 50%: 'cik' has a pattern but no description, and 'concept' carries its own schema description. The tool description adds no meaning to either parameter, so it fails to compensate for the undocumented 'cik' field even though it implies a company-scoped search.

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 (Search) and resource (SEC XBRL facts) plus a scope qualifier (latest observations). The word 'compact' implicitly contrasts with the sibling sec_company_fact_search_evidence, but the differentiation is left for the agent to infer rather than stated explicitly.

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?

'FREE beta' signals cost/availability but gives no when-to-use guidance, no prerequisites, and no rule for choosing this basic tool over the adjacent sec_company_fact_search_evidence sibling. The agent must guess at the selection criteria.

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