list_threads

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

No annotations are provided, so the description carries the full burden. It discloses that the tool returns compact summaries (no full content), that invalid filter values silently return empty results, and that it is a fallback browse tool. It could additionally mention read-only behavior or permission requirements, but for a listing operation this level of disclosure is solid.

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 well-structured: it front-loads the most critical usage guidance (fallback, prefer search_index) and then provides a detailed Args section. While slightly long, every section earns its place given the lack of schema descriptions. The organization aids readability and quick scanning.

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?

The description covers purpose, usage trade-offs, all parameters, and return behavior (compact summaries). The output schema (present per context) handles return value details. No critical gaps are apparent for a list operation; it even explains the relationship to related tools and index syncing behavior.

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 schema has 0% description coverage, but the description's Args section thoroughly documents all six parameters: course_id, limit, offset, sort, filter, and category. It provides defaults, max values, valid filter categories, and specific examples (e.g., sort='new', 'top', 'trending'). This fully compensates for the schema gap.

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 a thread-listing fallback, states its scope (freshest N threads, sort options, personal/triage filters), and explicitly distinguishes it from the preferred search_index tool and from get_thread/get_course_thread for reading full content. The verb+resource ('list threads') is specific and unambiguous.

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?

Usage guidance is exemplary: it explicitly says to prefer search_index for almost all browsing, lists the exact conditions where list_threads is appropriate (freshness, personal/triage filters), and directs to get_thread/get_course_thread for reading a specific thread. This provides clear when-to-use and when-not-to-use guidance with named alternatives.

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