Set run directory

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

Annotations already declare it as a non-read-only, non-destructive, non-idempotent, open-world mutation, so the safety profile is covered. The description adds one useful behavioral constraint – the directory must already exist inside the site root, i.e. it will not create it – but says nothing about whether nginx is reloaded, permissions required, or failure behavior.

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 sentences, front-loaded with the effect and followed by the precondition. Every clause earns its place with no 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 simple two-parameter setter with full schema coverage and no output schema, the description supplies the purpose plus the key precondition. It is nearly complete; only operational details such as restart/reload implications or error handling are absent, which is acceptable at this complexity.

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 both id and runPath are already documented in the schema. The description reinforces that runPath is relative to the site root and must exist, adding modest value but no format or syntax detail beyond the schema's own '/public' example. 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 (change the directory nginx resolves requests against) and the scenario it serves (entry point in a subdirectory like /public). Sibling tools such as site_set_index and site_set_rewrite are clearly distinct in subject matter, though no sibling is named explicitly.

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?

Gives a concrete condition for use: apps whose entry point lives in a subdirectory such as /public. It does not state when to avoid this tool or point to alternatives (e.g., site_set_index for default index files), but the triggering context is clear.

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