generate_link_preview

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

Annotations provide readOnlyHint and openWorldHint. Description adds concrete behavioral details: fetches up to 2 MB HTML and 1 MB image, SSRF-safe, optionally uploads blob. No contradictions.

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?

Three well-structured sentences, no redundancy. Front-loaded with core purpose, each sentence adds unique value.

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?

Given one parameter, output schema exists, and annotations present, the description fully covers prerequisites, alternatives, security, and process. Highly complete.

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 covers URL format and constraints (100% coverage). Description adds meaning by explaining the extraction process (OG/meta tags, blob upload) and return type. Baseline 3, plus extra context.

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 it generates a link preview with title, description, and thumbnail, specifying the verb 'Generate' and resource 'link preview'. It details the process (fetching, extracting meta tags, uploading thumbnail) and distinguishes from sibling tools like upload_image and upload_video.

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 says 'Use this tool before create_post when you want a rich URL card; use upload_image or upload_video for local media instead.' Also mentions authentication requirement and rate limiting.

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