read_thread

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

Beyond the readOnlyHint annotation, the description discloses the output format (markdown) and the structural components returned (root, self-thread, top replies). It also reveals a convenient behavior: any tweet in the thread can serve as the input. This adds meaningful context without contradicting annotations.

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 two sentences long with no filler. It front-loads the primary purpose, then gives a practical input tip. Every word contributes to understanding the tool.

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?

With an output schema present and read-only annotations, the description covers the core behavior well: what is read, in what format, and how to specify the thread. It doesn't explain how max_replies affects 'top replies' or timing behavior, but the schema defaults and output schema reduce the need for that detail.

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 should compensate. It only hints at the meaning of url_or_id ('Pass any tweet in the thread') but provides no explanation for max_replies or include_replies. Even though the parameter names are somewhat self-explanatory, the description fails to add value beyond what the schema already states.

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 clearly identifies the tool's purpose with a specific verb ('Read') and resource ('full X thread as markdown'). It explicitly lists the thread components (root post, author's self-thread, top replies), making it distinct from sibling tools like read_tweet or read_replies.

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?

The phrase 'Pass any tweet in the thread' gives concrete guidance on how to invoke the tool. While it doesn't explicitly contrast with alternatives, the description's emphasis on 'full thread' and 'top replies' implies it is intended for thread-level reading rather than single-tweet or replies-only use.

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