List categories

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds payload context (ids, descriptions, topic counts) that the agent cannot get from annotations or the empty schema, which is real added value. It stops short of noting the tree's hierarchy depth or whether counts are live, so not a 5.

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 sentences, zero waste. The return content is stated first and the routing guidance second, which is the right front-loading for a lookup tool.

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?

With no output schema, the description carries the return-value burden itself and does so ('ids, descriptions and topic counts'). Combined with annotations covering the read-only/open-world profile and a paramless schema, an agent has everything needed 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?

Zero parameters, so the baseline of 4 applies. There are no arguments for the description to explain; the sentence correctly signals the tool is unconditioned by input.

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?

Specific verb (List) plus resource (forum's category tree) with scope detail: 'with ids, descriptions and topic counts'. That tells an agent exactly what comes back and distinguishes it from sibling reads like get_topic or search_forum.

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?

Explicitly states the purpose in workflow terms: 'Use it to find the category id to pass to search_forum, list_recent_topics, or investigate_issue.' That names three concrete downstream alternatives and the condition that selects them, leaving nothing to inference.

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