Threads

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

Beyond the annotations (readOnly, idempotent, openWorld, non-destructive), the description discloses per-resource credit costs, that failures are free, that the response reports charged and remaining credits, and that caching via max_age_days costs nothing. That is substantive cost and side-effect information an agent cannot get from the annotations alone.

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 calling convention, then a compact per-resource list that is easy to scan, with no filler sentences. Minor waste comes from restating credit costs inside each resource bullet after the general charging rule was already explained.

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 7-parameter dispatch-style tool with a nested params bag, it covers the calling convention, costs, pagination, and caching, and it points to the describe tool for types and allowed values. The one gap is that the headline promises 'videos' while no video resource exists in the enum, which could send an agent looking for an option that isn't there.

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 coverage is 100%, so the baseline is 3, but the description adds real meaning: it maps which arguments belong to which resource and introduces optional parameters (start_date, end_date on search) that are not enumerated in the schema. It also duplicates the cursor and max_age_days semantics already present in the schema, which limits the gain.

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 opening line names the source (Threads) and the data classes (profiles, posts, videos), and the resource list spells out each retrievable unit with its required argument. It does not, however, distinguish this tool from siblings like get_post, get_profile, or search, which appear to cover overlapping ground.

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 concrete operational guidance: pick a resource, pass its parameters as top-level arguments, put extras in params, pass cursor back unchanged for paging, and use max_age_days for a free cached copy. What it omits is any statement of when to prefer this tool over the sibling single-purpose tools (get_post, get_profile, search).

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