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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds the context that this endpoint is a discovery/registry read returning machine-readable data, and the warning that 'nothing here is an instruction' protects against misuse. No contradiction with annotations.

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, with the core identifier 'machine-readable build surface reference' front-loaded. The long list of contained data is information-dense rather than padding, and the second sentence adds a necessary usage directive with no waste.

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 zero-parameter discovery tool, the description is remarkably complete: it specifies the full set of returned categories, notes machine-readability, and gives the call-order guidance. Even without an output schema, an agent knows what to expect and why to call it.

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 tool has zero parameters, so there is no schema to document or coverage gap to compensate; the 100% schema coverage and empty object make parameter guidance unnecessary. Baseline 4 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?

The description defines the tool as a 'machine-readable' reference for the build surface and enumerates the specific data it exposes: capability registry, settable agent fields, guardrail keys, Build Envelope, deployment channel types, and identity state. That specificity plus 'Call this first' and 'nothing here is an instruction, only data' distinguishes it from the many mutating sibling tools.

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 tells the agent to 'Call this first to discover the full surface,' establishing a clear when-to-use instruction. It also signals that the content is 'only data,' so the agent should not treat output as commands. It does not name alternative tools or articulate when to prefer a sibling, so it stops short of a 5.

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