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

With no annotations, the description carries the full burden and does so richly: it declares "Read-only", documents the 403 on non-member company_id, explains gap semantics (merged coverage windows, internal holes reported, ZCT-509), and discloses the 10/account cap on period_gaps with an exact period_gap_count. It also clarifies that "Reconciled" means matched entries, not ledger=balance, and that non-zero suspense blocks a clean VAT close.

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 purpose and the primary clarification (what "Reconciled" means) are front-loaded before the endpoint comparisons and gap mechanics. It is dense and cross-reference heavy, but most sentences earn their place given the composed behavior; slightly long for a status tool.

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 and no annotations, the description still conveys the return surface (per-account entry-status counts, in_suspense counts, latest closing balance, company-level GL Suspense balance) plus the caveats that matter for correct interpretation. Nothing essential for calling or interpreting it is missing.

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 0% for the single company_id parameter, so the description must compensate. It adds meaningful semantics: the parameter is a CompanyMember identifier, and an explicit non-member company_id yields 403. This is real added meaning, though format details remain implicit.

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 composed resource ("Composed bank snapshot") and frames it with a concrete question ("is my banking up to date?"). It explicitly distinguishes itself from siblings by naming the three endpoints it replaces (bank-accounts, coverage, reconciliation/summary) and calls out what those still cannot answer.

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 states when to use this tool (one call for bank snapshotting) versus alternatives ("use …/reconciliation/completeness per month"), and notes it is not period-scoped. It even enumerates the gaps the three substitute endpoints would leave, leaving nothing to inference.

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