Add bookmark

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

Adds context beyond annotations by stating duplicate rejection and return of created bookmark with id. No contradiction with annotations (readOnlyHint=false, etc.).

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 sentences with zero waste; front-loaded with the primary action and key behaviors.

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?

Covers core behavior, duplicate rejection, and return value. With full schema and annotations, it's mostly complete, though could mention scope (user's own list) or error handling.

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 all parameters are described in the schema. Description adds no additional parameter-level meaning beyond what's in 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?

Description clearly states the action ('Save a URL to the user's reading list'), the specific resource, and distinguishes from siblings like delete_bookmark and mark_read by focusing on creation.

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?

Mentions rejecting duplicates, which implies not to add existing URLs, but lacks explicit guidance on when to use this tool versus alternatives like search_bookmarks or mark_read.

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