list_thread_items

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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, but the description adds meaningful behavior: the whole thread is fetched once and sliced locally, `next_offset` signals continuation, and results are budgeted by `max_total_chars`. That pagination model is real context beyond the 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?

Two dense sentences that front-load the purpose, then cover the call cost, return shape, pagination, and continuation. Slightly packed, but each clause carries information useful for correct invocation.

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 10-parameter read tool with annotations and no output schema, the description supplies the return shape (`items[]` plus referenced entities), the slicing parameters, and the continuation pointer. That is sufficient for an agent to call it correctly.

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 100%, so the schema already documents each of the 10 parameters in detail (including the '+1 call' cost notes). The description adds only the integrated 'pass exactly one' constraint over the id params, which is marginal beyond what the schema provides; baseline 3 is appropriate.

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 names a specific verb+resource ('One thread as structured items') and clarifies the granularity (items[], not a rendered document), which distinguishes it from get_thread_markdown without naming that sibling explicitly. An agent can tell it returns structured thread data rather than a formatted report.

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 routing guidance for the id parameters: use `topic_id` for 1 call vs `discussion_id`/`poll_id` for 2 calls, and 'pass exactly one'. This helps an agent pick the efficient path, though it does not explicitly state when to prefer this tool over get_thread_markdown or list_threads.

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