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

Annotations already establish the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds genuinely useful behavioral scope beyond them: the availability window of actuals (2019-20 to 2024-25) versus estimates (2025-26, 2026-27), which tells the agent what data can exist. 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?

Two sentences, front-loaded with the core verb and resource, and every clause carries information (grain, comparison basis, year scope, mode switch). The first sentence is dense with stacked comma clauses, which slightly hurts scannability but is not padding.

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 tool with two optional parameters, full schema coverage, and annotations carrying the safety profile, the description covers what an agent needs: the returned grain, the year availability, and the omit-name listing behavior. Absence of an output schema is a minor gap since 'by program' only hints at the returned structure, but nothing required to invoke it correctly 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 coverage is 100%, so the baseline is 3; the description earns an extra point by adding meaning the schema omits — the full valid year range and the actual-vs-estimates distinction tied to the year parameter, plus the omit-name behavior. It does not restate the name-matching semantics, which the schema already covers.

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?

Names a specific verb and resource and pins down the exact data grain: a provincial department's gross spending by program, showing actual against amended and original estimates. That precision makes it easy to distinguish from a generic budget or totals call, but the description never names or contrasts the closely overlapping siblings (get_budget, get_totals, get_pay), so it stops 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?

Gives concrete usage context: it states the valid fiscal-year scope and the important mode switch, 'Leave out name to list the departments and years,' which tells the agent how to get department enumeration instead of a single department. It offers no when-not guidance or explicit alternatives to the similarly-named budget/totals tools.

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