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

Annotations already cover the safe-read profile (readOnly, idempotent, closed-world), and the description adds real behavioral detail on top: articles, news, and press releases come back in full, while reprints and partner press are truncated to an excerpt with a link, and long posts are paginated via offset. It omits error behavior for an invalid id and whether offsets beyond the end are safe.

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 first clause is front-loaded with the core action, and every sentence carries information (fields, id provenance, excerpt policy, pagination). The phrasing is dense and slightly awkward ('by the id list_blog_posts or search gave'), but there is no filler.

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 3-parameter read tool with annotations and no output schema, the description covers what is returned, how truncation and excerpts work, and how to page. Only edge-case behavior (bad ids, offset past the end) is unstated, which is a minor gap.

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%, so the baseline is 3; the description earns a step up by explaining that some post kinds return only an excerpt, which is important context for interpreting chars and offset. The id and chars semantics themselves are left entirely to the schema.

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 gives a specific verb and resource ('Get one blog post'), states the return fields (title, kind, author, date, text), and explicitly ties the required id to sibling tools ('the id list_blog_posts or search gave'), which cleanly separates it from list_blog_posts and search.

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?

It tells the agent where ids come from (list_blog_posts or search) and when to use offset ('to keep reading a long post past the first part'). It does not explicitly say when not to use it (for example, 'do not use this to browse posts, use list_blog_posts'), so it stops short of a full routing rule.

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