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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the hard-coded assumptions (single, no dependents, 16.5% abatement) that constrain the result and the fields returned. It could go further on input limits or edge cases, but this is solid added 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?

Front-loaded with the core operation and assumptions, then output shape, then a discovery pointer. Every sentence carries information, though the explicit 'Returns: {...}' field list is partly redundant given an output schema already exists.

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 read-only calculator with full schema coverage and an existing output schema, the description covers purpose, baked-in assumptions, and related-tool discovery. The endpoint reference ('/api/v1/salaire-net?pays=qc') is somewhat implementation-facing, but nothing an agent needs to call 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 description coverage is 100% and the single parameter (income_cad, annual employment income in CAD, minimum 0) is fully documented in the schema. The description's mention of 'employment income' only echoes the schema, adding no format, range, or unit detail beyond it, so the baseline 3 applies.

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?

States a specific verb and resource ('combined Quebec + federal income tax') plus the exact scope conditions (employment income, single, no dependents, 16.5% abatement). This implicitly separates it from the single-jurisdiction siblings calculate_quebec_income_tax and calculate_canada_federal_tax, so an agent can route correctly without opening the schema.

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 clear qualifying context: employment income, single filer, no dependents, plus a concrete data source ('same engine as /api/v1/salaire-net?pays=qc') and a pointer to list_bundles for related calculators. It does not explicitly say when to prefer a sibling over this one (e.g. vs. calculate_quebec_income_tax), so no exclusions are stated.

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