Bookmark Post

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

Annotations already provide key behavioral traits (readOnlyHint=false, destructiveHint=false, idempotentHint=true, openWorldHint=true). The description adds the 'authenticated user' prerequisite, which is useful context, but does not disclose additional side effects or error behavior. This is adequate given the annotation coverage.

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?

The description is a single, concise sentence with no filler. It is front-loaded with the action and target, making it immediately clear.

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 single-parameter tool, the description is complete: it names the resource, the authentication context, and the input method. Annotations cover safety and idempotency, and there is no output schema to explain. Minor omission is explicit error handling, but not necessary for this simple operation.

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?

The input schema provides 100% coverage with a clear description of tweet_id ('The ID of the post'). The description's 'by its ID' aligns with the schema but does not add new meaning, so it relies on the schema for parameter semantics.

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 clearly states the action ('Add') and the resource ('post to the authenticated user's bookmarks') with a specific method ('by its ID'). It distinguishes from siblings like x_remove_bookmark (removal) and x_get_my_bookmarks (listing), leaving no ambiguity about the tool's function.

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 and resource: bookmarking a post when the user wants to save it. However, there is no explicit guidance on when to use this versus alternatives, nor any exclusions or prerequisites beyond the implied authentication requirement.

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