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

With only readOnlyHint in annotations, the description carries the behavioral burden and does so richly: available=false means no verified row with provenance keys ABSENT, an unreachable store is REFUSED (DATA_UNAVAILABLE), prose is truncated at ~2400 chars, legacy rows before 2026-09-13 mislabel source_form and blank source_period, and caveats ride tool_notes. These are non-obvious failure modes an agent must know before calling.

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 purpose and return shape, and nearly every clause is actionable. It is dense and the backfill/restamp operational detail is somewhat niche, but no sentence is filler given the absent output schema.

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?

No output schema exists, so the description enumerates the returned keys (summary, available, business_summary, short_summary, provenance fields) and warns that `summary` is NOT the content. Failure-state, truncation, and freshness caveats are all covered; nothing needed to call it correctly is missing.

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?

One parameter at 100% schema coverage, so the schema already documents ticker format. The description adds only indirect meaning (ticker is resolved against SEC annual reports, with 20-F handling for foreign private issuers); baseline 3 is appropriate when the schema does the heavy lifting.

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+resource ('First-party business summary for a ticker') and pins the source to SEC 10-K Item 1 / 20-F Item 4, plus characterizes content as a 'curated, verifier-gated overview of what the company does.' It is clearly separable from sibling data tools like get_fundamentals and ol_filing_search.

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 routes passage-level retrieval elsewhere ('For semantic passage retrieval over the full filing corpus use ol_filing_search'), which is genuine when-to-use guidance. It doesn't address the other nearby siblings (search_company, get_fundamentals), so differentiation is partial rather than exhaustive.

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