close_group_membership

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

Beyond the annotations (readOnlyHint false, idempotentHint false, destructiveHint false), the description adds concrete behavioral details: it refuses memberships that already have an end (`already_ended`) or an end before start (`ends_before_start`), and preserves earlier facts. These are not present in annotations, adding valuable context. However, it does not describe the success response or any side effects beyond the record update, but this is minor given the mutation 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 concise (three sentences) and front-loaded with the core purpose, then usage, then constraints. Every sentence adds distinct value, and the structure is clear and scannable.

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 simple two-parameter schema and the existence of an output schema (not provided), the description covers purpose, usage, and constraints well. It lacks explicit mention of how to obtain a membership ID or the expected date format, but for a straightforward closure operation it is largely 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 schema has no descriptions (0% coverage) and the tool description does not explicitly explain the format or meaning of `ended_on` (e.g., date format) or how to obtain `membership_id`. It only implicitly suggests that `ended_on` is the last day the membership held, which is insufficient for an agent to correctly construct the parameters.

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 states a clear verb ('Record the last day') and resource ('a historically true membership'), and distinguishes this from the sibling tool `correct_record` by noting it is for valid memberships that ended, not for correcting wrong records. This provides a precise, unambiguous purpose.

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?

It explicitly says 'Use this when someone left a group' and directs users to `correct_record` with entity type `group_membership` when a stored membership was simply wrong. This gives clear when-to-use and when-not-to-use guidance, directly addressing the main alternative.

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