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

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds valuable context beyond that: it clarifies the auth requirement ('Pass a SIGN-IN-WITH-X header value you signed locally'), explains that 'a read burns no nonce' (no side effects), and details the uniform 404 response for inaccessible posts. No contradictions with annotations.

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 efficient; every sentence contributes essential information. It is front-loaded with the core purpose, followed by usage guidance, error behavior, and authentication instructions. There is no redundancy or filler. The length is justified by the amount of useful context provided.

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?

Despite lacking an output schema, the description proactively lists the fields returned (bodyMd, tags, status, url, answer card). It covers error behavior, authentication, source of the postId, and relationship to sibling tools (update_essay, get_article). For a read operation of moderate complexity, all essential context is present.

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% with both parameters documented. The description adds minor contextual value by stating 'Pass a SIGN-IN-WITH-X header value you signed locally' for signInWithX and connecting postId to the output of specific sibling tools. However, the schema already adequately describes the parameters, so the description's added semantic value is limited.

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 reads back one of your own posts in full by ID, listing specific fields (bodyMd, tags, status, url, answer card) and explicitly distinguishing it from get_article (public read surface, can't show drafts) and update_essay (wholesale replace). The verb 'Read back' and resource 'one of your own pieces' are specific and 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 explicit when-to-use guidance: 'Do this BEFORE an update_essay' with reasoning (edit stored source vs remembered version). It contrasts with get_article and tells how to obtain the postId (from publish_essay or list_my_posts). It also explains the 404 error behavior for missing/others'/deleted posts, setting clear expectations.

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