Close experiment

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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered. The description adds genuinely non-obvious behavior beyond that: the elicitation form is client-dependent, and a failed/declined confirmation leaves the experiment open, meaning the call may be a no-op rather than a partial mutation.

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 confirmation contract is front-loaded in the first sentence and the fallback path follows logically. The passive phrasing ("The confirmation form is elicited when the client supports it") is slightly indirect, but nothing is redundant or padded.

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?

With an output schema present, return values need no explanation, and the description fully covers the two-phase confirmation protocol an agent must understand to avoid a silent no-op. It omits whether closing is reversible and what permissions are needed, which are minor given destructiveHint is already set.

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 50%: the confirm parameter is documented in the schema, and the description reinforces its meaning (only true after a person has agreed) as the elicitation fallback. experiment_id carries no description anywhere, though its meaning is self-evident from the name, so this lands at 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 first sentence gives a specific verb and resource ("Mark an experiment closed") and adds the gating condition ("after the user confirms"). It is trivially separable from siblings such as create_experiment, list_experiments, and draft_readout without opening any schema.

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 clearly states when to call it (after user confirmation) and what to do when elicitation is unavailable (call again with confirm=true), plus a negative case (declining/cancelling does not close). It stops short of naming sibling alternatives, but for a terminal-state mutation the when/when-not guidance is explicit.

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