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

Annotations already cover the read-only, idempotent, closed-world safety profile, and the description adds substantial context beyond them: the exact statutory basis, the payment formula, what the optional balance/rate path computes (interest subsidy, $50 principal match, 360-payment projection to payoff or cancellation), and the assumption of constant income. The provenance note (copied from statute text, not model memory) is a meaningful trust signal for a calculation tool.

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?

Purpose and statutory grounding are front-loaded, followed by formula then optional-output behavior, so the ordering is sensible. It is dense and formula-heavy in a single block, but nearly every clause conveys computational or trust-relevant information rather than 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?

With no output schema, the description takes on the job of explaining returns, and it does so reasonably: base payment, first-month breakdown, and the payoff/cancellation projection. It does not describe the response shape or units for the projection (e.g., month count vs. total paid), which is a minor remaining gap for a four-parameter calculator.

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 schema carries the baseline, but the description still adds meaning: it explains that dependents subtract $50 each from the monthly figure, that rate is only meaningful together with balance, and that AGI is banded in $10,000 increments with a $120 floor and 10% top rate. That gives the agent a mental model of how each input moves the result.

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 (calculates the RAP monthly payment) and anchors it with the governing statute and effective date. It is clearly distinguishable from siblings like compare_rap_vs_standard and get_plan_transition_dates, which do comparison and date lookup rather than a single-payment computation.

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 implied by the formula and by the note that supplying balance and rate additionally yields a first-month and payoff projection, so an agent can infer when the optional params matter. However, it never says when to prefer this over compare_rap_vs_standard or get_plan_transition_dates, and gives no exclusions or preconditions beyond the effective date.

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

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

Annotations already declare this as a safe read-only, idempotent operation, but the description adds substantial behavioral context: it lists the returned metrics, discloses the assumption of constant income and on-time payments, and notes which plans count for PSLF. Those are meaningful execution details beyond the structured 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 description is front-loaded with the comparison and remains compact for a five-parameter financial tool. The long parenthetical listing the Tiered Standard income thresholds is informative but dense and could be structured more cleanly.

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?

Given the tool's complexity, lack of an output schema, and safe read-only annotations, the description is complete enough to call correctly. It names the compared plans, conditions, returned values, key assumptions, and PSLF treatment.

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%, so the schema already documents each parameter thoroughly. The description reinforces the conditional role of the loan-date parameter and the constant-income assumption for AGI, but it does not add syntax or interpretation beyond what the schema provides.

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 ('Compares') and names the exact plans being compared: RAP, Tiered Standard, and conditionally the 10-year Standard plan. This is far more specific than the sibling calculate_rap_payment tool and makes the tool's scope immediately clear.

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 clearly establishes the comparison context and states the condition under which the 10-year Standard plan is included. It does not explicitly direct the agent away from calculate_rap_payment or explain when a single-plan calculation would be preferable, so it stops short of full alternative routing.

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

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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), and the description adds real domain behavior: results change at the July 1, 2026 statutory boundary, proration applies to less-than-full-time enrollment, and an interim exception exists for borrowers enrolled with a loan on June 30, 2026. It stops short of describing the response structure or what happens for dates far outside the stated regimes.

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 purpose sentence is front-loaded and the statutory/date specifics follow in one dense block. Density is justified by the reference nature of the data, though the trailing undergraduate-limits sentence is closer to output preview than invocation guidance.

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?

Two optional parameters, no output schema, and the description supplies all the substantive framing an agent needs: what is returned (annual and aggregate caps per borrower type), the effective-date regimes, proration, and the interim exception. There is no output schema, yet the enumerated amounts effectively preview the return content.

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 baseline is 3; the description goes beyond it by explaining why 'date' matters (the pre/post July 1, 2026 regime split) and by giving substance to each borrower_type value (dependent vs independent undergraduate ranges, graduate, professional, Parent PLUS per dependent student). It does not clarify the 'all' enum value or the today-default behavior beyond what the schema says.

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?

Opens with a precise verb+resource+scope: 'Returns federal Direct Loan borrowing limits in force on a date.' The resource (loan limits) is unmistakably distinct from the repayment-plan siblings (transition dates, RAP payment, RAP vs standard), so an agent can route 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?

Usage is implied by the date-scoped framing ('in force on a date'), which signals this is a point-in-time lookup, but the description never states when to prefer it or what to do instead when a question is about repayment rather than limits. No explicit when-not or alternative routing is given.

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

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds real value beyond that by disclosing what the response contains — each step marked past or upcoming against a supplied date, plus a current status per plan — which tells an agent how the data will be shaped.

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?

Purpose is front-loaded in the opening clause, but the sentence then packs six enumerations of dates and deadlines into a single semicolon-chained run-on. That detail is largely payload an agent will receive upon calling, so it costs readability without changing the decision to invoke.

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, single-optional-parameter tool with no output schema, the description supplies what an agent needs: the domain, the content returned, and the past/upcoming semantics. Only explicit invocation guidance is missing, which is minor given the narrow scope.

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% and the schema already defines on_date with format and default. The description only echoes this with 'against a date' and adds no syntax, timezone, or edge-case guidance beyond the structured field, 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 — 'Lists the dated steps of the federal student loan repayment overhaul' — and the enumerated content makes the scope unmistakable. None of the siblings (payment calculators, loan limits) retrieve timeline data, so an agent can route correctly without opening a 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?

Usage is only implied: the enumeration of plans and dates suggests 'call this when the user asks about a plan timeline or deadline,' but there is no explicit when-to-use, no when-not-to-use, and no mention of the sibling tools as alternatives. An agent must infer the trigger condition.

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