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

Annotations already declare the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description still adds useful behavioral context beyond that: it returns the full document text (not a snippet) and includes the address to cite, which is a real output-side trait.

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?

One taut sentence, front-loaded with the action and resource, with the citation detail attached. No padding or boilerplate; only minor overlap with the title.

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 single-parameter read tool, an output schema is present (so return values needn't be explained) and annotations carry the safety profile. The description supplies the missing context — the link to `search` and the nature of the returned content — leaving only explicit usage sequencing unstated.

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 sole `id` parameter is fully documented in the schema, including the 'forfait:confort' example format. The description adds nothing about the parameter beyond what the schema already provides, which is the expected baseline when the schema does the heavy lifting.

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?

States a specific verb (rend / returns) and resource (full text of a flytel.fr document), enumerating the document types (forfait, guide, question fréquente) and noting it also returns the address to cite. It ties itself to the sibling `search` as the source of the id, which differentiates it cleanly even though the bare name 'fetch' is generic.

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?

Usage is implied rather than stated: the description makes clear this reads a document previously found by `search`, so an agent can infer it must call search first. There is no explicit when-not or exclusion guidance, leaving the sequencing to inference.

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