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

Beyond the readOnly/openWorld/idempotent annotations, the description discloses critical behavioral quirks: legal-entity and consolidated group accounts are listed apart and never add up, confidential filings are omitted, missing fiscal years are not zeros, and amounts are in euros as filed. This is exactly the kind of context an agent needs to avoid misinterpreting results.

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 front-loaded with the resource and data items, then usage examples, then essential caveats. Every sentence adds distinct value: content, use cases, accounting perimeter nuance, confidentiality/missing data behavior, and units. No filler or redundancy.

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 a read-only financial data tool with no output schema, the description is remarkably complete: it names the available metrics, the entity scope, the units, the meaning of missing data, and the critical consolidation caveat. An agent has enough context to select, invoke, and interpret results correctly.

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% and the single parameter 'siren' is already well-documented with pattern and SIRET-to-SIREN conversion guidance. The description adds contextual meaning by tying the data to 'this SIREN' and the legal entity perimeter, but the schema already carries the load, so a baseline 3 is appropriate.

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 starts with a specific verb+resource: 'The annual accounts one French company filed with the business register, fiscal year by fiscal year' and enumerates exact fields (revenue, gross margin, EBITDA, EBIT, net income, thirteen ratios). It clearly distinguishes this tool from siblings focused on announcements, timeline, and insolvency by specifying financial accounts content.

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 'Use this to answer' questions about revenue, profitability, turnover evolution, and indebtedness, which is clear when-to-use guidance. It does not explicitly name sibling alternatives or state when not to use it, but the use-case framing is strong enough to guide selection.

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