list_activities

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 lists activity types and notes 'Free (0 credits)', which implies no cost, but lacks details on permissions, rate limits, response format, or whether it's read-only (implied by 'List' but not explicit). For a tool with zero annotation coverage, this is insufficient behavioral context.

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 a single, efficient sentence that front-loads the core purpose ('List available activity types') and adds essential details (categories and cost). There is zero waste, making it highly concise and well-structured for quick understanding.

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?

Given the tool's simplicity (0 parameters, no output schema, no annotations), the description is adequate but has gaps. It explains the return value (activity types and cost), which is good, but lacks usage guidelines and full behavioral transparency. For a low-complexity tool, this is minimally viable but not fully complete.

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 input schema has 0 parameters with 100% coverage, so no parameters need documentation. The description adds value by explaining what the tool returns (activity types with categories and cost info), which compensates for the lack of output schema. This exceeds the baseline of 3 for high schema coverage.

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 states the verb 'List' and the resource 'available activity types', specifying the categories (FREE, PUBLIC, PRIVATE). It distinguishes from siblings like 'create_activity' or 'list_sessions' by focusing on activity types rather than sessions or creation. However, it doesn't explicitly differentiate from all siblings (e.g., 'get_stats' might also involve activity data).

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?

The description provides no guidance on when to use this tool versus alternatives like 'list_sessions' or 'get_stats'. It mentions 'Free (0 credits)' which hints at cost implications but doesn't specify context or prerequisites for usage, leaving the agent to infer when this tool is appropriate.

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