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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful context: which filing types are valid and that max_chars bounds the output per section. It stops short of describing return structure or rate limits, but with an output schema present that gap is minor.

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 tight clauses with the core capability and the identifier scheme front-loaded, followed by the routing sentence. No redundant or filler text; every phrase carries information.

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 an output schema present, return values need no explanation, and read-only annotations cover the safety profile. The description supplies the extraction semantics, valid filing types, identifier options, and sibling routing, so nothing an agent needs 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?

Schema coverage is 100%, so baseline would be 3. The description adds a relationship the schema does not express explicitly: you must supply accession AND either cik or ticker, and max_chars bounds output. That clarifies the alternative-identifier constraint beyond the raw property list.

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 (Extract) and resource (selected item sections), gives concrete examples (1A Risk Factors, 7 MD&A) and bounds the filing types (10-K, 10-Q, 8-K). An agent can immediately distinguish this from sec_filing or sec_financials.

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 to alternatives: sec_filing for the filing, sec_financials for statements, sec_full_text_search for keyword discovery. Each alternative is named with the condition that selects it, leaving nothing to inference.

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