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

Annotations already declare destructiveHint=true and idempotentHint=true, and the description goes beyond them by scoping the destruction: contacts are untouched and only the previous name is overwritten. That is exactly the kind of blast-radius clarification an agent needs before mutating, though it doesn't mention failure behavior for a nonexistent ID.

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, zero filler, with the primary action front-loaded and the side-effect note immediately after. Nothing could be cut without losing meaning.

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?

A simple two-parameter mutation with no output schema; the description plus annotations and schema together give the agent enough to call it correctly. The only gap is error/nonexistent-list behavior, which is minor.

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 100%, so both parameters are fully documented in the schema, including the ID source (directiq_list_lists) and the 1–200 character name constraint. The description adds only the 'by ID' framing, so baseline 3 is appropriate.

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 ('Rename a contact list by ID'), which clearly separates it from create_list, delete_list, and get_list. It doesn't distinguish itself from the sibling directiq_rename_tag, leaving that differentiation to the resource noun alone.

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?

Usage is implied by the verb – rename an existing list – but there is no explicit statement of when to prefer this over alternatives or what prerequisites exist (e.g. list must exist). An agent can infer, but nothing is spelled out.

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