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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds modest value by disclosing the statement's structure (operating, investing, financing), but says nothing about currency scope, multi-company behavior implied by openWorldHint, or the effect of compare_type on the response shape.

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 resource and its sections. The trailing 'GET /cash_flow' is implementation detail rather than agent-facing meaning, a minor bit of low-value payload in an otherwise tight description.

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?

No output schema exists, so the description does need to signal the return shape, and the parenthetical section list does that adequately for a read-only report. The fully described 3-parameter schema covers the input side, so only comparison-output semantics are left unstated.

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%, including the enum semantics for compare_type and the 'custom' interaction with start_date/end_date, so the schema carries the parameter burden. The description adds no parameter detail beyond 'for a period', which is the baseline-3 case.

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 names a specific report ('cash flow statement') and enumerates its sections (operating, investing, financing), so an agent knows exactly what data comes back. It does not explicitly distinguish itself from jurnal_get_balance_sheet or jurnal_get_profit_and_loss, which are the obvious confusable siblings, leaving the agent to infer the choice from the name alone.

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 only implied: 'for a period' suggests this is the per-period aggregated cash view, but there is no explicit statement of when to pick this over the balance sheet or P&L, nor any prerequisite or caveat. No exclusions or alternative-routing guidance is given.

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