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

Annotations already cover read-only/idempotent/non-destructive, and the description adds genuinely new operational context: only the derived sheet (no company name or number) is sent to the model, the call is quota-charged, and identical figures are served free from cache. Privacy, billing and caching behaviour are exactly the traits an agent cannot get from structured fields.

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?

Three sentences, no filler, and the deliverable is front-loaded ahead of the operational caveats. Slightly dense in the middle clause but every sentence 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?

With no output schema, the description still tells the agent what comes back (a plain-English reading plus anything needing attention before filing) and how the input is handled. Combined with the verbose schema, an agent has everything needed to call it correctly.

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 description coverage is 100% and every nested figure carries its own definition, so the schema does the heavy lifting. The description adds no additional parameter meaning (e.g. currency-unit assumptions or what the figures object must contain), so baseline 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?

States a specific verb+resource (a plain-English reading of a set of figures/derived balance sheet) and makes the audience and deliverable explicit ('written for a director who is not an accountant'). It does not differentiate from the nearby sibling check_accounts, which plausibly also surfaces issues 'before filing', so an agent could confuse the two.

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?

Implies usage context (needs a human-readable narrative for a non-accountant before filing) but never states when to pick this over check_accounts or sample_accounts, nor any prerequisites. The routing must be inferred.

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