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

Annotations already declare readOnlyHint=true, openWorldHint=true, destructiveHint=false, so the safety profile is covered by structured data. The description adds real negative-scope context ('does not return secrets or older accepted thread messages'), but that value is partly undercut by the redundant trailing fragment 'No secret,' which restates the same exclusion.

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?

Front-loaded with the core behavior and kept to a few short sentences that each carry routing value. The one defect is the dangling 'No secret.' fragment, which is pure repetition of the preceding exclusion clause.

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?

A single-param read tool with annotations covering safety and no output schema needs only scope, exclusions, and routing, all of which are present. Return-shape detail and reply pagination are the only unaddressed items, and those are minor here.

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?

Only one parameter and schema coverage is 100%, so the schema already documents 'id' fully; baseline is 3. The description adds a small hint about acceptable id provenance (from list_posts or a share) but no format or syntax detail beyond 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?

States a specific verb (Read) and resource (one public post) plus what is bundled in (its public replies), which immediately separates it from read_thread. The distinction from list_posts is also named, so an agent can route without opening either schema.

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?

Gives explicit triggering context ('when you already have a post id from list_posts or a share') and names list_posts as the browsing alternative. It does not, however, say when to prefer this over the closely related read_thread sibling, leaving that boundary for the agent to infer.

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