get_discussion

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

Goes well beyond readOnlyHint/openWorldHint: breadth-first ordering, depth carried as a field rather than nesting, deleted/dead comments skipped entirely, and exactly how truncation manifests. The truncation contract (truncated flag, truncation_hint, comments_with_hidden_replies, top_level_shown vs top_level_total) is precisely the behavioral context annotations cannot convey.

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?

Front-loaded with purpose and ordering, then parameters, then truncation, then exclusions — a sensible arc with no filler sentences. It runs longer than most definitions need and the truncation paragraph restates fields the output schema likely already names.

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 5-parameter read tool with annotations and an output schema, everything an agent needs is present: what comes back, in what order, how to tune the budget, and how to detect partial results. Nothing material is left to inference.

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 already 80%, so the baseline would be 3, but the description adds genuine meaning to max_top_level by explaining the budget trade-off against max_comments ("without it the comment cap is spent entirely on opening statements"). story_id and comment_chars get no added treatment.

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?

Opens with a specific verb and resource ("Read a Hacker News comment thread in one call") and clarifies the return shape ("the story plus a flat list of comments"), which implicitly separates it from get_story. It never names a sibling explicitly, so the boundary with get_story is inferred rather than stated.

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?

Gives concrete operational guidance: lower max_top_level to read an argument in depth, raise it to survey opinions broadly, and notes big threads will not fit. It stops short of saying when to reach for get_discussion instead of get_story or search_stories.

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