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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the mutation profile is covered. The description adds genuinely non-obvious behavior beyond that: counts halt with the stop and a subsequent experiment on the same widgets starts fresh rather than resuming. It doesn't say whether historical results remain readable afterward.

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 compact sentences, the core action first and the non-obvious consequence second. Nothing extraneous.

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 destructive, open-world mutation with no output schema, the description covers the semantic effect but omits what happens to the experiment's collected results and whether anything is returned. Adequate but with a real gap.

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 project parameter is documented in the schema, but widgetId has no description anywhere. The description mentions neither parameter, so it fails to compensate for the undocumented required widgetId.

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: 'End a running experiment.' An agent can tell this apart from start_experiment, though the description never names that sibling explicitly, leaving the pairing implicit.

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?

Usage is only implied — 'End a running experiment' suggests it applies to active experiments, and the note about starting a new one hints at the start_experiment counterpart. No explicit when-to-use/when-not or prerequisites are given.

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