list_active_threads

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

With no annotations, the description carries the full burden and does well: it discloses that the tool traverses channel history to oldest, judges activity using latest_reply, excludes reply bodies, and truncates message text to the first line. It does not discuss error conditions or rate limits, but the core behavioral quirks are transparent.

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 one dense, front-loaded paragraph: purpose first, then selection algorithm, exclusions, truncation behavior, and how to set 'since'. No sentence is filler; the parenthesis about get_thread_replies earns its place by routing to a sibling.

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 moderately complex polling tool with no output schema and no annotations, it covers inputs, selection logic, return limitations, and the polling usage model. It would be slightly stronger if it specified the exact fields returned (e.g., the thread identifier to pass to get_thread_replies), but an agent can invoke it correctly from the information given.

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%, giving a baseline of 3, and the description adds real value: it tells the caller to pass the previous polling time to 'since' and explains 'oldest' as the lower bound for traversing parent messages. This is practical guidance beyond the schema's field labels.

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 opens with a specific verb and scoped resource: a polling tool that returns only items with activity since 'since'. It clearly distinguishes itself from get_thread_replies by stating reply bodies are not included, and it names the extraction criteria (new posts or threads with new replies), so an agent can tell what the tool does.

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: it is for periodic polling and since should be the previous polling time. It also points to get_thread_replies with oldest as the alternative for reading reply bodies. However, it does not explicitly state when not to use this tool versus the other siblings like get_channel_history or resolve_user, though their purposes differ.

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