Add an existing user to a specific Kaiten card using their user ID. Use it to grant card access or membership without creating a duplicate user.
Add an existing user to a card using user_id.
| Name | Required | Description | Default |
|---|---|---|---|
| card_id | Yes | ||
| user_id | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| item | Yes |
Changes observed during successful MCP inspections.
v1.0.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the mutation profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=true), so the description's lower bar is largely met. It adds the useful precondition that the user must already exist, but says nothing about permissions, duplicate handling, or what happens on failure.
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?
A single front-loaded sentence with zero filler. It is efficient, though arguably too terse given the documentation gaps elsewhere.
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?
An output schema exists, so return values need not be described. For a mutation tool with undocumented parameters, however, the definition omits prerequisite/permission context an agent would need to invoke it reliably.
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 0%, so the description must compensate for both parameters. It names user_id and clarifies it refers to an existing user, but card_id is never mentioned and neither ID's format or origin is explained.
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?
States a specific verb and resource ("Add an existing user to a card") and names the key parameter (user_id). It is distinguishable from siblings like kaiten_remove_card_member and kaiten_update_card_member_role, but it does not explicitly reference them.
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 phrase "existing user" hints at a precondition, but there is no explicit guidance on when to use this versus kaiten_update_card_member_role or how it differs from kaiten_list_card_members. An agent must infer the workflow.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.