Update

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

With no annotations, the description carries the full burden of behavioral disclosure, and it only states that fields are changed partially. It does not mention required identity lookup, error conditions, folder restrictions for URL (though the schema hints at that), or any side effects of the mutation.

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, focused sentence with no filler. The key behavioral point ('only the fields given') is included, and the description is appropriately small for a simple update operation.

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 basic 3-parameter update with no output schema and no annotations, the description is minimally viable but leaves gaps: it does not state that 'id' is required, does not clarify folder restrictions, and does not describe what happens after a successful update. These are important for reliable invocation.

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 only 33%, and the description adds little beyond the schema property names. It does convey that only provided fields are updated, but it does not explain the role of 'id' as the bookmark identifier, the relationship between 'url' and folders, or any constraints on 'title'.

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 uses a clear verb ('Change') and specifies the resource ('bookmarks') and the exact scope ('title and/or URL'), which distinguishes it from the sibling create/move/remove tools. It is less explicit about which sibling it is not, but the update semantics are clear.

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 phrase 'only the fields given' implies partial-update usage, so an agent can infer this is for modifying specific fields rather than replacing or deleting. However, there is no explicit guidance on when to prefer this over create/move/remove, nor any conditions or prerequisites like requiring an existing bookmark id.

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