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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the mutation profile is covered. The description adds value beyond that: plan gating, cost (0 credits), and the non-destructive pause-via-is_active behavior. It doesn't cover reversibility of field changes or partial-update semantics for the 9 optional fields.

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?

Short, front-loaded, and scannable with a clear REQUIRED marker and a one-line cost note. Minor redundancy: the Pro/Enterprise requirement is stated twice, which costs a little space.

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?

The safety profile is covered by annotations and there is no output schema to explain, so the essentials are present. However, for an 11-parameter partial-update mutation with 27% schema coverage, the description is thin on how unspecified fields are treated and what the other nine parameters mean, leaving gaps an agent would want filled.

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 27% across 11 parameters, so the description carries a heavy burden it largely does not meet. It documents the required id and repeats the is_active pause semantics already present in the schema, but says nothing about prix_min/prix_max, surface bounds, type_local, code_postal, code_departement, or webhook_url replacement behavior.

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 (Update) and resource (existing webhook alert), which cleanly separates it from create_market_alert, delete_market_alert, and list_market_alerts. It does not explicitly name a sibling, but the verb+resource pairing is unambiguous.

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?

Gives real usage context: the Pro/Enterprise plan prerequisite, the required id sourced from list_market_alerts, and the tip to use is_active:false to pause instead of deleting. It stops short of explicit when-not-to-use-this-tool guidance or pointing at update_portfolio_property-style alternatives.

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