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

The description richly discloses behavior beyond the readOnlyHint and idempotentHint annotations: balances are sync-anchored snapshots, CREDIT accounts may return BALANCE_FETCH_ERROR or BALANCE_CONSENT_ERROR, rows may degrade to last-synced data with realtime:false, and the response shape is given. This is substantial behavioral context.

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 description is long but dense; every sentence adds operational detail such as failure modes, degraded behavior, and response wrapping. It is front-loaded with the core purpose and endpoint, and the caveats follow a logical progression, though the length could challenge quick scanning.

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 single-parameter tool with no output schema, the description is remarkably complete: it covers request format, staleness semantics, error cases, degradation behavior, and the exact response shape. An agent has enough information to invoke it correctly and interpret results.

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?

With 0% schema description coverage, the description adds essential meaning by specifying that account_ids must be 'an array (1–50).' The schema only says it is an array of strings, so the description contributes cardinality and usage intent beyond the structured definition.

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 opens with a specific verb and resource: 'Returns the latest available balance per account id (GET /accounts/:id/balance).' It clearly distinguishes this from sibling tools like openfinance_force_sync and openfinance_list_transactions by framing the balance as a snapshot tied to the last sync.

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?

It gives explicit usage context: if the balance seems stale or disagrees with openfinance_list_transactions, run openfinance_force_sync and re-read. It does not explicitly enumerate when not to use this tool, but the guidance for alternatives is concrete and actionable.

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