Assign card user

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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds nothing beyond repeating the HTTP path — no note on whether an existing assignee is replaced, whether reassignment is additive, what permission level is needed, or whether the assignee is notified.

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 lines, action stated first, no filler. The endpoint line is defensible as a light param hint, though it consumes half the description's budget for little return.

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 four-parameter mutation with no output schema and no structured parameter documentation, this is thin: nothing on user_id format, on success/failure semantics, on how to resolve board/stack/card IDs, or on permission requirements. An agent can name the operation but cannot confidently construct a correct call from this alone.

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 description coverage is 0%, so all four required parameters are undocumented. The URL template weakly implies board_id, stack_id and card_id are path-scoped identifiers, but user_id gets no explanation at all — whether it is a username, an internal UID, or a display name is left entirely to guesswork, which is the single most error-prone parameter here.

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?

"Assign one user to a card" gives a specific verb and resource, and the raw endpoint path pins it to the Deck cards API, so it is distinguishable from sibling mutators such as nextcloud_add_participant or nextcloud_add_user_to_group. It stops short of explicitly contrasting with those siblings, so 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?

There is no guidance on when to use this versus the other add/assign-style siblings, and no prerequisites such as the target user needing to exist or already be a member of the board. The only usage signal is the URL template, which is implicit at best.

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