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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavior beyond annotations: it fans out across many sources, returns sources_used/sources_failed so empty sections mean 'no data' rather than a bug, resolves company names via SEC EDGAR, returns resolved:false for private companies instead of a bare failure, and accepts 'company'/'ticker' interchangeably. This is rich, honest disclosure of what happens under the hood.

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 description is dense and long, but every clause earns its place: query examples, the 'always prefer' directive, the cross-source fan-out, the resolved:false behavior, and type semantics. It front-loads the purpose and usage, though the middle source-list section is a heavy block of parentheticals that could be slightly tightened. For the amount of behavioral context needed, the density is justified.

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?

Given that there is no output schema, the description carries the responsibility of explaining return contents, and it does: cik, company_name, resolved_from/resolved_to, recent_filings with URIs, fundamentals, and sources_used/sources_failed. It explains failure semantics, private-company behavior, and input alternatives. A callable agent has everything needed to decide, invoke, and interpret results.

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%, and the schema already describes both parameters well. The description still adds meaning by showing example values ('AAPL', '0000320193', 'Moderna'), clarifying that type's enum values are interchangeable, and explaining the resolution behavior for names. It slightly overlaps with the schema, but it enriches the practical semantics of value with concrete formats and edge-case behavior.

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 opens with concrete example queries ('Tell me about X' / 'research Acme' / 'brief me on Tesla'), then a specific verb phrase: 'full cross-source profile of a US public company in ONE parallel call'. This clearly distinguishes it from siblings like resolve_entity, compare_entities, deep_research and single-source SEC/XBRL/news lookups. The scope (US public company), the output components and the accepted input shapes (ticker/CIK/name) are all explicit.

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 explicitly says 'ALWAYS PREFER over chaining single-pack SEC/XBRL/news lookups when the user asks for a holistic view', naming the alternative pattern it replaces. It also states when it is NOT the right tool: for private companies (resolved:false with an explicit notes line) and mentions that person/place coverage is 'coming soon', implying limitations. That is strong routing guidance.

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