Open a post

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description echoes 'Read-only.' The description adds useful detail about expanded text and engagement counts, but these are return-content details rather than additional behavioral caveats. No contradiction exists.

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, front-loaded sentence that states purpose, return content, and read-only nature with no filler. Every part earns its place.

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?

Even without an output schema, the description lists the expected return fields (author, text, timestamp, engagement counts, attribution, external link), making expectations clear for a simple read-only tool. It lacks error-case or URL-format caveats but remains adequate for the tool's low complexity.

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% for the single parameter post_url, which is described as 'Permalink to the post.' The description repeats 'by URL' but adds no new format, validation, or usage details beyond the schema. Baseline 3 applies where schema carries the semantic weight.

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 tool's function: 'Open a single post by URL and return its full content' and enumerates specific return fields (author, text, timestamp, engagement counts, attribution, external link). This is a specific verb+resource that distinguishes it from sibling tools like read_post by emphasizing URL-based retrieval and expanded content.

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?

Implied usage is for fetching a specific post by permalink, but the description does not explicitly state when to use this tool versus alternatives like read_post or get_post_details. No exclusions or alternative scenarios are provided, so guidance remains implicit.

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