Join Group

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

Goes beyond annotations by disclosing the social side effect ('Groupmates and instructors see that you joined') and by restating the irreversibility and the required two-step confirmation. The destructiveHint=true annotation already flags mutation, but the description adds the concrete consequence and the safety protocol, which is the useful part.

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?

Three short clauses, front-loaded with the verb and resource, then the visibility consequence, then the safety directive in brackets. Nothing redundant and the most important constraint is easy to spot.

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?

Covers the action, its visibility impact, and the destructive two-step requirement, which is sufficient for a 2-parameter mutation with no output schema. It stops short of describing failure modes (group full, not self-signup, already a member), which an agent would benefit from before calling.

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 100% and both parameters (group_id, confirm) are already documented with their semantics in the schema. The description reinforces the confirm protocol but adds no formatting, validation, or format detail beyond what the schema provides, so baseline 3 applies.

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 ('Join a ... student group') plus a scoping qualifier ('self-signup'), which distinguishes it from groups that require invitation. It does not name the sibling it complements (leave_group, list_my_groups), so differentiation is implicit rather than explicit.

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 confirm=true preview-then-execute workflow is spelled out, which is genuine usage guidance for invoking it. However, there is no guidance on when to choose this over leave_group or on prerequisites — e.g. whether the group must be in the self-signup category, whether it can be full, or whether joining is allowed after a prior leave.

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