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

Annotations already declare readOnlyHint=false and destructiveHint=false, but do not reveal that the write path sends an e-mail and creates an external trial. The description discloses that the login link is e-mailed to the user and 'never returned', which is genuinely non-obvious side-effect information. It omits what the response looks like when the account already exists and whether repeated calls create duplicate trials, so it stops short of full transparency.

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?

Front-loaded with the hard constraint ('myide link only') and then the trigger condition, which is the right ordering for an agent scanning for applicability. The second sentence is dense but every clause carries load (condition, parameters, approval gate, e-mail delivery). Slightly run-on, but no 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?

For a six-parameter tool with no required fields and no output schema, the description covers the happy path and the safety gate well. It leaves open what the tool returns in the account-exists branch, what the type and contact parameters do, and whether a second call with ouvrir_essai on an existing account is a no-op or an error. Those gaps matter for correct invocation of a non-idempotent tool.

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 is only 17% (only 'abonne' is documented in the schema), so the description must carry the load. It does explain ouvrir_essai, societe, and confirmer with their conditional relationship, which is the most valuable part. However, 'type' (the agence/particulier enum) and 'contact' are left completely unexplained in both places, and the interaction between them and the trial creation is unclear.

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 names the concrete resource (a SynergieLoc management account tied to the signed-in myide user's e-mail) and the two modes: a lookup, and a conditional 30-day trial creation. No sibling tool in the list does account provisioning, so the distinction is implicit rather than stated. The verb pairing 'tells whether ... exists' / 'opens a trial' is specific enough that an agent knows exactly what it gets.

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?

Explicit trigger: 'WHEN starting property management for the signed-in myide user'. Explicit scope restriction: 'myide link only'. Explicit branching rule: if no account exists, pass ouvrir_essai true plus societe, and only after the user's explicit approval pass confirmer true. That is a when-to-use, a precondition, and a human-in-the-loop gate all in one sentence.

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