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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the bar is lower. The description adds real domain behavior by disclosing the decision rules and thresholds that drive the result, but it never says what the call returns (eligibility verdict, weekly rate, lump-sum option) nor how missing optional inputs such as capital or householdOk are treated.

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?

A single front-loaded sentence opens with the jurisdiction and the resource, then packs in the thresholds with no filler. The dense parenthetical of figures is efficient but makes the sentence heavy to parse in one pass.

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 an 8-parameter calculation tool with no output schema, the description should say what comes back and how the unmentioned inputs (capital, householdOk, couple) affect the result; it does neither. It is complete on the policy rules it chooses to state, but leaves the agent guessing at the response shape.

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 88%, so the schema already documents each field and the baseline would be 3. The description goes beyond it by giving the actual comparison values behind incomeWeekly (€534 single, €640.80 from January 2027), tying qualifyingPayment to the under-66 path, and explaining the 2026 vs 2027 period distinction. It leaves couple, capital, and householdOk uninterpreted, keeping it from a 5.

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 ('check') and a precisely named resource ('Fuel Allowance means test' plus the 2026/27 season amount), so an agent can instantly tell it apart from siblings such as ireland_carers_allowance or ireland_working_family_payment. It stops short of naming the overlapping ireland_what_can_i_claim sibling, so routing between the two is left implicit.

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 by the topic: an agent can infer it should be called for Irish Fuel Allowance eligibility/amount questions. There is no explicit when-to-use, when-not-to-use, or reference to alternatives like ireland_what_can_i_claim, and no statement of prerequisites such as needing the applicant's age or income first.

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