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

Beyond the read-only annotations, the description discloses the default six-month window, newest-first ordering, post typing, canonical URLs, engagement counts, truncation behavior, and prompt-injection cautions. These are substantive behavioral details that help the agent interpret and use the results safely.

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 front-loaded with the core purpose and output shape, and the safety guidance is useful rather than filler. It is slightly dense as one paragraph, and the final 'Read-only' repeats the annotations, but overall it is efficient.

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 output schema reduces the need to explain return values, and annotations cover the read-only safety profile. However, with seven parameters and low schema description coverage, the missing explanations for several parameters make the definition only adequately complete.

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 very low at 14%, so the description must compensate, but it only clarifies `since`, `username` as a handle, and `agentName`. It does not explain `maxResults`, `includeReplies`, `companyId`, or `connectionId`, leaving several parameters ambiguous.

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 states a specific verb and resource: returns one X account's public profile and its posts, with ordering, item types, URLs, and engagement counts. It is clearly distinguishable from sibling connection tools, which cover GitHub activity, transcripts, files, messages, and searches rather than X posts.

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 gives clear usage context, including verifying the handle belongs to the subject and handling `truncated` output. It also instructs the agent to pass `agent_name`, but does not explicitly name alternatives or when not to use this tool.

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