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

Annotations already declare readOnly, idempotent, non-destructive, openWorld, so safety is covered. The description adds genuine beyond-schema context: it works on failed/canceled jobs, it never mutates state, and callers should wait between polls (rate-limit hint). It omits auth requirements and pagination/response-shape detail, keeping it from a 5.

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?

Four short front-loaded sentences: purpose, negative scope, further negative scope, and a polling caveat. No filler, though the opening 'Read an existing bulk file's...' slightly duplicates the title.

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?

There is no output schema, so the description carries the burden of describing returns — and it does, at a useful level (status, progress, aggregate counts, no per-email results). Combined with the annotations, an agent can call and interpret it correctly; only ID provenance and auth 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?

Schema coverage is 0% — the file_id property has only a numeric pattern and no prose. The description names it as 'its file ID' and thereby confirms its meaning, but does not say where to obtain the ID (presumably from millionverifier_upload_file) or clarify the numeric-string format. Marginal compensation for the coverage gap.

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 a precisely scoped resource: an existing bulk file's verification status, progress and aggregate result counts, keyed by file ID. The 'aggregate result counts' phrasing and the exclusion of per-email results clearly separate it from millionverifier_verify_email and millionverifier_upload_file.

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 explicit when-to-use context ('Includes failed/canceled jobs') and explicit exclusions ('without starting, stopping or re-verifying anything', 'Does not download individual email results'). The 'Wait between polls' note is actionable polling guidance. It stops short of naming the sibling tool to use for per-email results, so routing for that case is only implied.

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