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

Annotations already declare readOnlyHint=true, so the safe-read profile is covered without the description. The description adds the useful semantic note that a balance can be owed or held in credit, but says nothing about pagination behavior or whether results are capped despite listing limit/offset.

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?

Two short sentences, front-loaded with the core action and followed by the API mapping. Nothing redundant or padded.

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 read-only, fully schema-documented tool with no output schema, the description covers purpose, scope, and the key optional date dimension. Minor omission: no mention of what the balance payload contains or pagination limits, though the safety profile is handled by annotations.

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%, so client_ids, balance_date, limit, offset and class_id are all documented in the schema. The description reinforces the client_ids and balance_date semantics but adds no detail on class_id or paging beyond what the schema states. 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?

Specific verb+resource ('Get the account balance for one or more clients') with a clarifying gloss ('what they owe or hold in credit') and an explicit optional dimension (as of a date). No sibling tool touches client balances, so the agent can pick it out immediately.

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?

Usage is implied by the description — fetch balances for given client ids — but there is no explicit when-to-use/when-not guidance or reference to an alternative tool for related financial or client data. Adequate minimum, clear gap.

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