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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety bar is low, yet the description adds genuinely new behavioral information: the response includes auth scheme and username but 'Never the secret.' That credential-exposure disclosure is exactly the kind of thing annotations cannot convey.

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?

A single clause with no filler, and the key constraint — 'Never the secret.' — is placed at the end for emphasis. The telegraphic, fragment-like phrasing ('registries sandboxes install from') costs a little readability but wastes no space.

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 no parameters, no output schema, and full annotation coverage, the description is nearly sufficient: it names the resource and the returned fields. Explaining the return shape stands in for the missing output schema, though it doesn't say how many registries or how ordering works.

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 takes zero parameters, so there is nothing to disambiguate; the schema coverage is 100% by definition. Baseline 4 applies, and the description correctly spends no words on nonexistent inputs.

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 resource — the org's private package registries that sandboxes install from — and enumerates the fields returned (host, auth scheme, username). This is far more than a restated title, though it never names the sibling write tools (save_sandbox_registry, delete_sandbox_registry) to sharpen the boundary.

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 implied by the read-only listing nature and the readOnlyHint annotation rather than stated. There is no explicit when-to-use or when-not, and no pointer to save_sandbox_registry/delete_sandbox_registry for the mutating counterparts. Adequate but leaves routing to inference.

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