read_replies

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the read-only and external nature are covered. The description adds the markdown output format, which is useful. However, it does not disclose other behaviors like pagination, rate limits, or how the limit parameter affects results. With annotations present, this is acceptable but not rich.

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 that front-loads the action and output format. Every word earns its place, with no filler or redundancy.

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?

The tool is simple and has an output schema, so the description need not explain return values. However, it lacks guidance on parameter semantics (particularly limit) and usage context. Given the low schema coverage, the description partially compensates but leaves gaps that the agent must infer from the name and siblings.

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 0%, so the description must explain parameters. It implies url_or_id refers to the X post, but does not explicitly describe the accepted format (URL vs ID) or the meaning of 'limit'. The parameter names and constraints exist in the schema, but the description adds minimal semantic value beyond the obvious.

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 uses a specific verb 'Read' with a clear resource ('replies to an X post') and output format ('as markdown'). It distinguishes from siblings like read_tweet (single post) and read_thread (thread), 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?

Usage is implied by the tool name and description ('Read the replies') but no explicit guidance is given about when to use this versus alternatives like read_quotes or user_timeline. The sibling names provide context, but the description does not mention them or exclude other scenarios.

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