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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=true, so the agent knows this is a repeatable mutating call. The description usefully surfaces the required auth scope, but it does not explain what makes the call 'destructive' — e.g. whether omitted fields are cleared or the record is fully replaced.

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?

Two short sentences, no filler, with the operation and its key front-loaded ahead of the scope prerequisite.

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 13-parameter mutation with destructiveHint=true and no output schema, the description omits the critical replace-vs-merge semantics: whether unlisted fields are wiped. That single missing detail leaves an agent unable to safely invoke the tool on a partially supplied payload.

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% and every parameter carries its own description, so the schema handles parameter meaning. The description adds only the fact that 'id' is the addressing key, which the schema's required list and uuid format already imply.

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 ('Update an existing vendor') plus the lookup key ('by ID'), which cleanly separates it from create_vendor, get_vendor and delete_vendor on the surface. It stops short of naming the obvious alternative sibling (bulk_update) for multi-record edits.

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 only guidance is a precondition ('Requires vendors:write scope'), which is genuinely useful. There is no statement of when to prefer this over bulk_update or how partial edits are expected to be made.

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