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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint, so the description does not need to repeat safety. The description adds critical behavioral details: 28 credits debited even on failure (missing filing, no such statement, or non-SEC), and light_weight_mode for a leaner payload. No contradiction with annotations.

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 rich but concise, front-loading the core purpose, then identification methods, then shortcuts and error behavior. It could be slightly shorter by omitting the API endpoint and documentation reference, but overall it is efficient and each sentence adds value.

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 the tool has no output schema but is a fetch operation with 6 parameters and multiple failure modes, the description covers all necessary usage instructions: identification alternatives, error conditions, jurisdiction limits, credit cost, and performance option. Nothing essential 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?

The schema already covers 100% of parameters with detailed descriptions (e.g., ticker examples, quarter formats, filing_id source). The description adds context on parameter combinations (filing_id OR ticker+fiscal_year) and notes light_weight_mode saves context, but mostly reinforces schema info. Baseline of 3 applies given high schema coverage.

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 clearly states it returns the filing's Balance Sheet with extracted line items, values, and periods. It identifies the filing via filing_id or ticker+fiscal_year and mentions the exact API endpoint. It also positions itself as a shortcut for get_filing_statement with a specific statement type, distinguishing it from siblings like get_income_statement.

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 explicitly says it is a fixed shortcut for get_filing_statement(statement_type='Balance Sheet') and notes it does not take role_label or statement_type, preventing misuse. It also states it returns 404 when the filing has no balance sheet, and is only for SEC filings, with other jurisdictions coming soon. This gives clear when-to-use and when-not-to-use guidance.

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