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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds valuable behavioral context beyond that: it reveals the call returns both Facts and Passages in one response, and that an empty Facts section should prompt reading Passages – a fallback behavior that is not obvious from annotations or schema. It also mentions interval-overlap matching for period parameters, which is a useful behavioral nuance.

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 three sentences with zero fluff. The core purpose is front-loaded, followed by the most important usage tip (ticker required), then the fallback behavior, then period semantics. Every sentence earns its place, and the structure makes it easy to scan.

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 an 8-parameter tool with no output schema, the description covers the essential facts: what it returns, how to handle an empty Facts section, and how to use period parameters. It does not explain every parameter, but the schema handles that. The main missing piece is guidance on tool selection (when to use this vs. filing_list), which is partially covered under usage_guidelines. Overall, it is complete enough for correct invocation.

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 description coverage is 100%, so the schema already documents all 8 parameters with detailed descriptions. The description adds meaning beyond that by explaining that period_start/period_end match by interval overlap and that fiscal_period sets granularity – details not present in the schema. It also reinforces that ticker is required, which is already in the schema but is a critical constraint. This goes beyond the baseline 3.

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 'Search one company's SEC filings' – a specific verb, resource, and scope. It then names the two output sections (Facts and Passages), which differentiates it from sibling tools like filing_list (likely listing filings) and news_search. An agent can tell this is the tool for searching a single company's financial filings without opening the schema.

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?

The description gives operational guidance: 'ticker is REQUIRED' and 'Pass an explicit period window for the most recent figure.' It also instructs to read Passages when Facts is empty. However, it does not explicitly state when to use this tool versus alternatives like filing_list or company_search. It implies this is for searching filings but never names a sibling or a condition that would route the agent elsewhere.

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