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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context about what the result includes ('including recurring expenses and CAPEX amortisation') and the breakdown dimensions. There is no contradiction with the 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 entire description is one tight sentence that front-loads the verb and resource, then adds only the two most informative details (breakdown dimensions and inclusion of recurring/amortisation). Every clause earns its place, and there is no redundant filler.

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?

The tool is a read-only filtered list with an output schema, and the annotations cover safety, so the description's single sentence is close to sufficient. The only real gap is the absence of usage-routing guidance relative to sibling tools, which is captured separately. For an agent deciding whether the tool fits, the description plus schema and annotations are enough.

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%; the schema already documents start_date, end_date, category, and include_capex with formats and defaults. The description does add the 'by category and vendor' framing, but that more describes the output than the parameters. Baseline 3 applies because the schema carries the parameter documentation.

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 uses a specific verb ('Get') with a named resource ('OPEX and CAPEX expenses') and defines the output breakdown ('by category and vendor') over a date range. It also names unique inclusions ('recurring expenses and CAPEX amortisation') that set it apart from siblings like get_revenue_breakdown or get_pnl_summary. Even without naming a sibling explicitly, the content clearly identifies what this tool returns.

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?

The description implies the usage context (when an expense breakdown is needed) but gives no explicit 'use this instead of X' guidance or exclusion boundaries. Alternatives like get_revenue_breakdown or get_combined_pnl are not mentioned, leaving the choice to inference. This is better than nothing but below the explicit routing bar.

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