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

Annotations already cover read-only, idempotent and non-destructive, so the description's job is to add context — and it does, by declaring a deliberate exclusion of the original document and secure file URL, which is exactly the kind of data-sensitivity fact an agent must know before calling. It stops short of describing behavior for inaccessible/nonexistent assignments.

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 front-loaded sentence with zero filler; the positive scope comes first and the exclusion second, which is the right order for an agent deciding whether to call it.

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 output schema, the description steps in to sketch the return (status and dates) and rule out the sensitive fields, which is enough for a single-call read tool. Minor gap: the exact fields returned and error semantics are unstated.

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?

One required parameter with 0% schema description coverage, so the description carries the burden and largely fails: it never explains that assignmentId is the UUID of the assignment being read, nor what happens with a malformed or unowned ID. Only the phrase 'an accessible assignment's status' indirectly ties the parameter to a credential assignment.

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 (read) and the exact payload it returns: an assignment's status and relevant dates, plus an explicit negative scope (never the original document or secure file URL). The only weakness is that the name says 'credential details' while the description talks about an 'assignment', and it does not name the near siblings get_credential_type or get_credential_workflow_state.

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?

There is no when-to-use/when-not guidance and no reference to alternatives, even though the sibling list contains several credential reads that an agent could easily confuse this with. The word 'accessible' hints at a permission precondition but that is left implicit.

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