update_url

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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds useful side-effect context beyond annotations: only one URL entry is touched and 'the other fields on the object are untouched.' It does not cover permissions or undo behavior, so it is not a 5.

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?

Front-loaded with the action and scope, then the add_url contrast, with a short illustrative parenthetical. Three sentences, none wasted.

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 targeted mutation tool, the description covers purpose, scope, the add_url alternative, and non-target-field preservation, while annotations supply the safety profile and the schema explains match failure and all parameters. Nothing essential for correct invocation is missing.

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 every parameter is already documented in the schema. The description adds a usage rationale for correcting a wrong URL type, but no parameter syntax or constraint 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+resource+scope: 'Edit or remove ONE existing URL entry on a person, place, or repository.' It distinguishes from the sibling add_url ('add_url can only append'), so an agent can select it without opening another 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?

Explicitly names the alternative add_url and the condition that selects this tool: correcting an existing entry, with the Find a Grave example. This clearly establishes when to use this tool versus the append-only sibling.

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