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

The destructiveHint=true annotation already signals mutation risk, and the description adds useful behavioral context: it writes .mythex/run.json, starts a preview, and specifies the expected web service port. It does not explicitly state whether existing run.json content is overwritten, so it is strong but not exhaustive.

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 dense but front-loaded with the action and side effect, then moves through port details, config shape, deploy requirements, and API proxy behavior. Every sentence contributes operational information without filler.

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 config-writing mutation tool with no output schema, the description supplies the key context an agent needs: what file is written, that a preview starts, the expected service structure, deploy shapes, and the API proxy convention. Safety is covered by the destructiveHint annotation, and parameters are covered by the schema.

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%, so the schema already documents the two parameters. The description adds meaningful semantics beyond the schema by explaining the services array shape, deploy requirements for static vs server services, and the port/proxy setup.

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 specific verb and resource: 'Write .mythex/run.json and start the platform preview.' It also distinguishes this tool from using a shell for long-lived app servers, so an agent can identify the right tool without ambiguity.

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 long-lived app servers belong here rather than in a shell, giving a clear use case and alternative. It does not explicitly compare against siblings such as start_preview for simpler preview needs, so it falls short of full when/when-not guidance.

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