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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is largely covered structurally. The description adds the vendors:write scope requirement, which is genuine value beyond the annotations, but it omits the critical update semantics for a destructive tool — whether omitted fields are left unchanged or cleared.

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 with zero filler; the core action is front-loaded and the scope requirement follows immediately. Nothing could be cut without losing information.

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 tool, the schema and annotations cover most of what an agent needs, and no output schema means return values need not be described. The main gap is update/patch semantics and any field constraints (e.g., whether status has allowed values), which the description never addresses.

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% with 13 documented parameters, so the schema already carries parameter meaning and baseline 3 applies. The description adds nothing about which fields are updatable or how arrays like categories are replaced, so it does not exceed the schema.

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 gives a specific verb and resource ('Update an existing vendor by ID'), which is clear and actionable. It does not differentiate from siblings such as bulk_update or update_vendor_site_assignment, but the name/verb pairing with the update_* family 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?

It states a prerequisite ('Requires vendors:write scope'), which is useful context for when the call will succeed. However, there is no guidance on when to use this single-record update versus bulk_update, nor any note on how to handle partial updates, leaving usage conditions mostly implied.

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