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

The annotations already declare readOnlyHint=true and openWorldHint=true, covering the read-only nature and the possibility of external changes. The description does not add behavioral context beyond the purpose (e.g., side effects, auth requirements, rate limits). It neither contradicts the annotations nor enriches them, so a baseline score is appropriate 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, focused sentence: 'Get a single Bluesky post by URL.' It is front-loaded with the essential verb and resource, and contains no filler or redundant information. Every word serves a purpose, achieving maximum conciseness for a simple GET tool.

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 one-parameter, read-only retrieval tool, this description is nearly complete. It specifies the input (URL) and the action (get), which is sufficient for an agent to invoke it. The absence of an output schema is mitigated by the expected behavior of a 'get' tool, and annotations cover safety. The only minor gap is that it doesn't explicitly state what the response contains, but that is typical for such tools and not a significant omission.

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 100% – the schema fully documents the 'url' parameter as 'Link to the Bluesky post.' The description's phrase 'by URL' is redundant with the schema and adds no new meaning. With high schema coverage, the baseline of 3 applies; there is no additional semantic value provided.

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 states a specific verb ('Get'), a specific resource ('a single Bluesky post'), and the method of identification ('by URL'). This clearly distinguishes it from sibling tools like bluesky_profile_get (which fetches a profile by handle) and bluesky_profile_posts_list (which lists posts for a profile), making the purpose unambiguous.

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 description gives clear context for when to use the tool: when you have a URL to a specific Bluesky post. It does not explicitly mention when not to use it or point to alternatives, but the 'by URL' condition effectively implies the use case, and sibling tool names provide natural differentiation. This aligns with clear context without explicit exclusions.

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