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

Annotations provide readOnlyHint=true, and the description goes well beyond that: it discloses live versus ledger-derived provider data, the approximate nature of total_usd_cents, the treatment of pending/unreviewed classifications, and warnings for unqueried providers. 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?

The core result is front-loaded in the first sentence, and later sentences add non-obvious caveats about provider derivation and pending amounts. The description is long, but almost every sentence carries a substantive behavioral constraint; it could be tightened slightly, but is not bloated.

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 balance endpoint with no required parameters and a rich output schema, the description covers provider behavior, estimate semantics, pending amounts, and warnings. It is complete enough for an agent to call the tool and correctly interpret results without external knowledge.

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 the baseline is 3. The description adds useful meaning for include_providers by explaining which providers are live vs ledger-derived and how 'cash' behaves, which affects parameter choice and result interpretation. It does not significantly extend org_id beyond the schema.

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 clearly states the tool returns current account balances across the organisation's connected money providers, with a specific resource and scope. However, it does not directly differentiate this from the sibling get_bank_balances, which may also return balances, so it falls short of full sibling differentiation.

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 context is implied: the description explains what balances are returned and provides guidance about interpreting estimates and pending entries, but it never explicitly states when to choose this tool over alternatives such as get_bank_balances or get_financial_summary. There are no exclusion conditions or alternative route names.

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