Read a public Threads account’s posts

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

Annotations already cover readOnlyHint and openWorldHint, but the description adds critical behavioral detail: it is read-only, costs 0 credits, requires a Threads connection, and—most importantly—explains that an empty list does not prove the account has no posts, listing three specific reasons (private, <100 followers, unapproved permission). This goes far beyond the annotations and prevents a potentially dangerous misinterpretation.

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 longer than typical but every sentence carries weight: it states the purpose, gives workflow context, and includes a critical warning. The most important caveat is emphasized with capitalization. It could be tightened slightly (e.g., repeating 'for' clauses), but it remains efficient given the behavioral nuance it must convey. Front-loading the purpose is done well.

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 read-only list tool with only two parameters and no output schema, the description is comprehensive. It covers the return type (recent public posts), the workflow context, authentication requirements, cost, and the critical empty-list caveat. An agent has everything needed to call it correctly and interpret results appropriately.

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?

The input schema already provides 100% coverage for both parameters, including accepted username formats and the limit default. The description adds no additional parameter meaning beyond what the schema states; it only mentions 'limit' indirectly via 'how many posts' which is already in the schema. With full schema coverage, the baseline of 3 applies, and the description does not materially elevate it.

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 as reading a public Threads account's posts, calls out the raw material for specific workflows (teardown, mine_angles, ad copy), and differentiates it from siblings like threads_profile (profile info) and list_threads_posts (own posts). It explicitly says 'Use it after threads_profile, or on its own when you already know the handle,' which distinguishes its scope.

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 description provides clear usage context: use after threads_profile or when you know the handle, and then use the returned content for drafting posts or planning ads. It does not explicitly name an alternative tool for cases like private accounts, but the caveat about empty lists guides the agent on when not to conclude absence of posts. This is strong guidance, though it lacks an explicit 'when not to use' statement.

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