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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description still adds real value by disclosing the return format ('as plain text') — important since there is no output schema — and by explaining the identifier concept. It does not cover failure behavior (not-found, private/unpublished blog), which keeps it below 5.

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?

A single sentence with the action, scope, and return format front-loaded, plus a parenthetical defining the key parameter. Nothing is redundant with the title or annotations.

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 two-parameter read tool with no output schema, the definition covers what the tool returns and how to identify the post, which is sufficient to invoke correctly. The remaining gap — behavior on missing or non-public posts — is minor but real.

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 50%: username is documented in the schema, but slug has no description there. The description compensates precisely, defining slug as 'the last part of the post URL', which is exactly the disambiguation an agent needs. Both required params are therefore covered between schema and description.

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?

States a concrete verb and resource ('Read one post... blog') and scopes it to a single post retrieved by slug, which separates it in spirit from list_blog_posts. It never names a sibling outright, so an agent gets the singular-vs-list distinction only by inference from 'one post'.

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?

Usage is implied: call it when you already have a slug for a specific post. There is no explicit guidance on when to prefer list_blog_posts or find_creator instead, nor what to do when the slug is unknown or the post is missing.

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