Set Scaleway bucket CORS rules (full replace)

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

Annotations already indicate this is not a read-only operation (readOnlyHint: false), is open-world (openWorldHint: true), and is idempotent (idempotentHint: true). The description goes beyond annotations by spelling out the destructive side-effect: existing rules not in the list are removed (full-replace). It also explains the consequence – loosening or restricting cross-origin access – which adds important risk context. No contradiction with annotations.

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 three tightly packed sentences. Front-loaded with the core action, immediately follows with the critical full-replace semantics in all caps, then closes with the security implication. No filler, no repetition of what's in the schema.

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 the tool has 3 parameters, 100% schema coverage, no output schema, and clear annotations (idempotent, not destructive), the description covers the essential behavioral nuance (full-replace) and consequence. No need to detail return values since output schema is absent. However, it could mention that sending an empty array would effectively clear all rules (though delete_bucket_cors exists). Still, completeness is high for the 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 description coverage is 100%, so the schema already documents all three parameters well (bucket name, region, rules array). The description clarifies that the 'rules' parameter is the COMPLETE set (not an incremental addition), which is a critical semantic distinction beyond the schema's 'The COMPLETE CORS rule set to apply.' This prevents the agent from mistakenly believing it can just append a rule.

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 states the verb 'Set' and the resource 'Scaleway bucket CORS rules'. It immediately clarifies the full-replace semantics, which distinguishes it from any partial-update or append alternative. The title also includes 'full replace' as a deliberate qualifier.

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 explicitly explains the full-replace behavior – the provided list becomes the complete rule set and existing rules not in the list are removed. It also mentions the effect: 'loosens or restricts browser cross-origin access'. While it doesn't explicitly tell when not to use it or name an alternative (like delete_bucket_cors to remove all rules), the behavioral note is strong enough for an agent to decide.

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