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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds the useful nuance that only receipts absent from an *approved* bill qualify (draft bills presumably still count) and that output is line-level with values. It says nothing about ordering, volume, or whether receipts partially billed are included.

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 dense sentence with no filler, and the defining scope ('not yet on an approved bill') is front-loaded. The parenthetical gloss (GRNI) is the only slight redundancy.

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 zero-parameter, read-only report with no output schema, the description covers what is listed, the unit of output ('line by line'), and that value is included. Only minor gaps remain: no indication of ordering or of how partially billed receipts are treated.

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 the baseline of 4 applies; there are no arguments for the description to disambiguate. The description correctly implies an unfiltered, full-dataset report rather than a query.

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 names the exact resource and its discriminating condition: goods received but 'not yet on an approved bill', i.e. the GRNI accrual. That qualifier distinguishes it from p2p_goods_received (all receipts) and p2p_bill_match without needing the schema. It stops short of naming a sibling explicitly, so it is clear but not maximally differentiated.

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 GRNI framing implies the period-end accrual use case, but there is no explicit 'use this when...' statement and no mention of alternatives such as p2p_goods_received or p2p_bill_match. An agent must infer the usage from the accounting term rather than being told.

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