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

Annotations already flag destructiveHint=true and idempotentHint=false, and the description explains exactly why: 'replacing all of its files: a live file not sent is removed' and 'atomically'. It adds preconditions the annotations don't carry (root index.html required, website files only, plan limits), so the agent knows what gets destroyed and what will be rejected.

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?

Three tight sentences, front-loaded with the operation and its destructive scope, then the siteId constraint, then inherited rules. No repetition of the title or 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 destructive 3-parameter mutation with no output schema, the description covers replacement semantics, atomicity, and deploy constraints — enough to call it safely. It does not say what the caller receives back on success/failure, which is the main remaining gap.

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 33% (siteId and files have no top-level descriptions), and the description compensates by explaining that siteId is required and that files is a full replacement set rather than a delta. The message parameter is left to the schema, which already documents it ('Shown in deployment history').

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 and resource ('Re-deploys an existing site atomically, replacing all of its files') and explicitly distinguishes itself from create-type siblings with 'siteId is required, so it never creates a new site'. An agent can route between update_site and deploy_site without opening either schema.

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?

Implies the create path belongs to deploy_site and frames this as the existing-site path, plus 'the same rules apply as for any deploy' gives context for what it inherits. It does not name deploy_site or patch_site directly as alternatives or state when not to use this tool, so the guidance is clear but not fully explicit.

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