add_list_member

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. 'Add a user to a list' implies a mutation operation, but it doesn't specify whether this requires authentication, what permissions are needed, if there are rate limits, or what happens on success/failure (e.g., duplicate adds). For a write tool with zero annotation coverage, this leaves critical behavioral traits undocumented.

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 action without unnecessary words. Every word ('Add', 'user', 'list') directly contributes to understanding the tool's purpose, making it optimally concise for such a straightforward operation.

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 moderate complexity (a write operation with 2 parameters) and the presence of an output schema (which should cover return values), the description is minimally adequate. However, with no annotations and low schema coverage, it lacks details on permissions, error handling, and parameter semantics, making it incomplete for safe and effective use without additional context.

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% description coverage, with parameters 'list_id' and 'user_id' undocumented in the schema. The description adds no semantic information about these parameters—it doesn't clarify what format they expect (e.g., numeric IDs, strings), where to obtain them, or if they reference specific resources. With low schema coverage and no compensation in the description, this falls short of the baseline.

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 'Add a user to a list' clearly states the action (add) and resource (user to list), making the purpose immediately understandable. It distinguishes this from sibling tools like 'remove_list_member' or 'get_list_members' by specifying the additive operation. However, it doesn't explicitly differentiate from other user-list operations like 'follow_list' or contextually similar tools, keeping it at a 4 rather than a 5.

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. It doesn't mention prerequisites (e.g., needing list ownership or permissions), compare it to 'follow_list' (which might have different semantics), or indicate when 'remove_list_member' would be more appropriate. Without such context, agents must infer usage from the tool name alone.

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