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

Annotations already cover read-only, idempotent, and non-destructive behavior, so the description adds meaningful context: 'Pro.' licensing, 'Watermark-free and not truncated' guarantees, and the exact output columns. 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?

Packs purpose, scope, output shape, and behavioral guarantees into a few short clauses. The header-row listing earns its place because there is no output schema to document the return format.

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 tool without an output schema, the description supplies the full CSV column list, scope, and non-truncation/watermark behavior. The only minor gap is explaining what 'Pro.' implies for licensing, though sibling license tools hint at 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?

Schema coverage is 100% for the single optional po parameter, and the description reinforces its meaning with 'just one PO's GRNs'. The description does not add syntax or constraints beyond the schema, but none are necessary here.

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 the exact operation ('Export ... as CSV') and the exact scope ('every GRN or just one PO's GRNs'), and lists the full header row. This clearly distinguishes it from siblings like grn_list or grn_get.

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?

Provides clear context for when to use it: CSV export of all GRNs or filtered to one PO via the optional po parameter. It does not explicitly name alternatives or exclusions, but the scope and optional filter are sufficient for correct selection.

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