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

Annotations already mark the tool as read-only and non-destructive. The description adds valuable behavioral context: returns a time series with latest restated values unless asOriginallyReported is set, each row includes actual period start/end, fiscal periods follow the company's own calendar, and a warning is raised when the selected alias ends materially before other facts (indicating a possible XBRL tag change). No contradictions 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 a single dense paragraph that efficiently conveys purpose, usage, and behavioral details. It front-loads the core action and then adds specifics. While it could be slightly more structured (e.g., bullet points for the warning or parameter clarifications), it is not overly long and every 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 8 parameters, no output schema, and moderate complexity, the description is highly complete. It explains the return type (time series, one row per fiscal period with period start/end), the default data treatment (latest restated), the warning mechanism, and scope exclusions. No output schema is needed because the description sufficiently describes the output structure.

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 baseline is 3. The description adds extra meaning beyond the schema: it explains the default behavior of asOriginallyReported, mentions that calling concept with an unknown value lists supported aliases, and clarifies the fiscalPeriod note about discrete Q4 rows. This pushes the score above baseline.

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 identifies the tool as retrieving a single financial concept over time for a company from SEC XBRL data, naming example concepts. It explicitly distinguishes from sibling tools (GetFinancialStatement for full statements, CompareFinancialFact for peer comparison) and mentions that dimensioned disclosures are out of scope.

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 provides explicit guidance on when to use this tool versus alternatives: 'For a full statement use GetFinancialStatement; to compare peers use CompareFinancialFact.' It also notes that dimensioned disclosures (e.g., customer concentration) are outside this tool, and instructs calling with an unknown concept to list supported aliases.

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