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

With no annotations provided, the description carries the transparency burden. It discloses important behavior: the tool never returns a bare number, and results include source, legal reference, verification date, and reliability level. It also fixes the value year to 2026. It could add edge-case behavior, but it is substantial for a simple lookup.

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 compact and front-loaded with the core purpose: 'Valeur du référentiel (sourcée + datée)'. Every phrase contributes useful information, including the source version, and there is no repetition or filler.

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 its simplicity, the description is complete enough: the input is a stable key and the output contents are enumerated. Since there is no output schema, describing the returned metadata fields is valuable. Minor gaps such as error behavior for an unknown key are acceptable for this tool's complexity.

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 for the single parameter is 100%, so the baseline is 3. The description reinforces that the key is a stable public key and that values are tax/pension constants, but it does not add material meaning beyond the schema, which already gives examples and the referentiel_recherche hint.

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 what the tool returns: the 2026 value of a tax or pension constant by its stable public key, along with source, legal reference, verification date, and reliability level. It distinguishes itself from search-oriented tools by emphasizing lookup by a stable public key, though it does not explicitly name a sibling.

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 implies the tool is for retrieving a specific sourced value when you already have the stable key, and the schema notes that keys can be listed via referentiel_recherche. However, it does not explicitly state when to choose this tool over alternatives or when not to use it.

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