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

Annotations already declare destructiveHint=true, idempotentHint=true, and openWorldHint=true. The description adds only that the list must be existing; it does not explain the destructive implication of renaming, permission requirements, or the presence of a dry_run safety mechanism.

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?

A single sentence with no wasted words, front-loading the action and target. It is efficiently structured, though its brevity contributes to gaps elsewhere rather than being over-concise.

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 simple three-parameter mutation with full schema descriptions and rich annotations, the description is minimally adequate. However, it omits any mention of dry_run behavior and does not contextualize the destructive renaming operation, leaving some agent-relevant context to structured fields.

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 including dry_run. The description mentions the name being updated but adds no further syntax or constraint details beyond what the schema provides, making the baseline 3 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: update the name of an existing contact list. It clearly distinguishes from create_list and delete_list by requiring an existing list, though it does not explicitly name sibling alternatives.

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?

Provides no guidance on when to use this tool versus create_list, delete_list, or unrelated update tools. It implies the list must already exist but does not state prerequisites or conditions under which updating the name is appropriate.

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