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

Annotations already declare this a safe, read-only, idempotent operation, so the safety bar is covered. The description adds genuine behavioral context beyond them: a similarity threshold of 0.40, that no generated answer is produced, that explicit references bypass normal matching, and provenance (official PDFs, corpus date, Etalab licence).

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 purpose and scope are front-loaded, and every sentence carries information (threshold, return fields, follow-up tool, provenance). The cost is the full bilingual duplication, which doubles length and repeats content, but it is deliberate for a French/English audience rather than 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?

With no output schema, the description compensates by enumerating the returned fields (article number, instrument title, official excerpt, PDF link, score). It also covers corpus scope, threshold, query phrasing, and the downstream read step, so an agent has everything needed to invoke it 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%, so the schema already documents all four parameters including the `objet` enum and limit bounds. The description only reinforces the `pays` recommendation, adding little syntax or semantic detail beyond what the schema provides, so the baseline 3 applies.

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 states a specific verb (semantic, article-by-article search) and a precisely scoped resource: 237 French tax treaty instruments across 126 countries. It distinguishes itself from siblings by naming the corpus (treaties vs. BOFiP/Legifrance) and by routing the agent to conventions_article for the follow-up read.

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?

It gives actionable routing: specify `pays` when the country is known, and read the returned article next with conventions_article. It also notes that explicit references like "article 18 Suisse" are resolved directly, which tells the agent how to phrase a query. It does not, however, contrast itself with conventions_get or explain when the sibling search tools are preferable.

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