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

Annotations already establish that this is a safe, idempotent, closed-world read, so safety is covered. The description adds a genuine trait beyond them: output is auth-dependent, with verdict, valuation, prices and analyst estimates only appearing when signed in to a plan. It does not discuss rate limits, empty/unknown-ticker behavior, or payload size, so it is not a 5.

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 sentences, front-loaded with the core resource and no filler or hedging. The return-value enumeration is dense but each item tells the agent what it will receive, which matters given there is no output schema. Slightly list-heavy with no grouping, which keeps it from a 5.

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 one parameter and no output schema, the description must describe the return payload, and it does so exhaustively, including the sign-in-dependent split between free and plan-gated data. What is missing is failure behavior for an invalid ticker and whether the response is large enough to warrant paging.

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?

There is a single required parameter with 100% schema description coverage ('US ticker, e.g. AAPL'), so the schema already carries the semantics. The description says nothing extra about ticker format, case handling, or what happens for non-US or delisted symbols. Baseline 3 applies 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?

The description names the resource (a single company's filed record) and enumerates the data families it returns: XBRL financials, segment revenue, filings, Form 4 trades, 13F holder counts, risk factors, earnings dates. That content list implicitly separates it from list_filing_events and search_companies. It never states the operation as a verb or explicitly contrasts a sibling, so it stops short of a 5.

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?

There is no statement of when to call this rather than search_companies, list_filing_events, get_trend, or get_fund_holdings, and no preconditions beyond the implied ticker requirement. The only conditional sentence concerns sign-in state affecting the payload, which is behavioral rather than routing guidance. An agent must infer usage from the sibling names alone.

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