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

With no annotations provided, the description carries the full burden, and it does well by stating the operation is 'safe' diagnostics and explicitly declaring 'Never key material.' This communicates the read-only, non-sensitive nature of the tool, though it does not discuss permissions, errors, or side effects.

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 two sentences with no filler. The purpose is front-loaded, the content scope is summarized efficiently, and the safety qualifier 'Never key material' is a single purposeful sentence that earns its place.

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 one-parameter read-only tool with no output schema, the description is reasonably complete: it states what is returned and signals the absence of sensitive material. It could add a note about whether the subject must already exist or whether any registration prerequisite applies, but this is a minor 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?

The schema already documents the single agent parameter with 100% coverage, including accepted formats ('Handle, ag1- genesis alias or sbj1- subject id'). The description only loosely refers to 'a subject' and does not meaningfully add parameter semantics beyond what the schema provides, so the baseline of 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?

The description clearly identifies the tool as credential-lifecycle diagnostics for a subject and enumerates what it returns: credential states, purposes, validity windows, and the current signing credential. It is specific enough to distinguish from sibling tools like rotate_credential and get_controller_status, which address different lifecycle aspects.

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?

The description conveys that this is a diagnostic, read-oriented tool, and 'Never key material' hints at what it is not for. However, it does not explicitly state when to prefer this tool over siblings like get_controller_status or get_agent_dossier, nor does it name alternatives or exclusion conditions.

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