Section 179 Deduction Calculator

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

Annotations already declare this as a read-only, idempotent, closed-world, non-destructive calculation, so the safety profile is covered. The description adds real behavioral value by enumerating exactly which figures are returned (first-year tax saving, first-year net cash, lifetime after-tax cost) and by clarifying the dependency on calculate_section_179 for the deduction input.

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 verb and core output list are front-loaded, which is good, but the long mid-sentence asset enumeration ('equipment, truck, tractor, RV, land, manufactured home, ATV, pontoon or other') duplicates the schema enum almost verbatim and inflates a two-clause idea into one sprawling sentence.

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 8 parameters and no output schema, the description usefully enumerates the return values (payment, total interest, first-year interest, tax saving, net cash, lifetime after-tax cost), which compensates for the missing output schema. The only gap is the relationship between first_year_deduction and the business share, which is left to the schema text.

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 all 8 parameters including the enum and the business_use_percent/marginal_tax_rate relationship are already documented in the schema. The description reinforces the after-tax trigger condition but adds no syntax or format detail beyond what the schema states, 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 ('calculates') plus a concrete set of outputs: monthly payment, total interest, first-year interest, and the after-tax cost breakdown for business assets. It also distinguishes itself from the sibling by name, telling the agent to use calculate_section_179 for the deduction amount rather than expecting this tool to return it.

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 usage context: use this for loan payment math, and add marginal_tax_rate or business_use_percent when the asset is a business asset to unlock the after-tax path; pair with calculate_section_179 for the deduction. No explicit exclusions or when-not guidance is given, which keeps it below a 5.

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 establish that this is a read-only, idempotent, non-destructive calculation. The description adds substantial behavioral context beyond annotations: the legal rule, effective dates, election effects, and the fact that bonus applies after any Section 179 deduction. It does not describe error behavior or return shape, but the core calculation behavior is well disclosed.

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 dense but front-loaded: it first states what the tool does, then supplies the necessary legal and date-based context. The length is justified by the complexity of the tax rule, though some citations and statutory detail could be trimmed without losing call 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?

For a complex tax calculation with no output schema, the description provides enough legal context, effective dates, election behavior, and Section 179 interaction to call the tool correctly. It could be stronger by explicitly stating the return values or edge-case handling, but it is largely complete.

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 all seven parameters are already documented in the input schema. The description reinforces key semantics such as written binding contract dates, reduced-rate elections, and Section 179 interaction, but it does not add much per-parameter meaning beyond what the schema already 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 states a specific verb and resource: it finds the IRC 168(k) bonus depreciation rate from acquisition and placed-in-service dates and applies it after Section 179. It is clearly distinct from a generic depreciation tool, though it does not explicitly name the sibling calculate_section_179 or vehicle-limit tools as alternatives.

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 gives detailed conditions for when bonus depreciation applies, including acquisition dates, placed-in-service dates, elections, and long-production/aircraft exceptions. However, it does not explicitly say when to use this tool versus calculate_section_179 or get_vehicle_depreciation_limits, so routing guidance is only implied.

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 a pure, idempotent, non-destructive read, so the safety burden is lifted; the description instead adds computational behavior: the dollar-for-dollar phase-out above the threshold, application of the business income limit, and reporting of the carryover. It also honestly discloses the tool's own limitation for 2027. It stops short of describing the response shape or what happens when the phase-out zeroes the deduction.

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 verb and the dollar thresholds that matter most, and every sentence carries content (limits, income limit, carryover, 2027 gap). The parenthetical citations are verbose, though defensible for a tax-calculation tool where authority matters.

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 carries the return-value burden, and it does signal the key outputs (deduction amount subject to phase-out, income limit, carryover) plus the 2027 out-of-range behavior. It is not fully complete: an agent cannot predict the exact response fields or how a fully phased-out deduction is reported.

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 all four parameters, making 3 the baseline. The description adds only marginal semantic value, notably that business_taxable_income drives the income limit and that the phase-out depends on total property cost — useful linkages, but not format, units, or edge-case detail beyond the schema.

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?

A specific verb and resource ("Calculates the Section 179 expense deduction as Form 4562 Part I does") leaves no ambiguity about what is computed, and the cited legal authorities anchor it precisely. It never names its siblings (calculate_bonus_depreciation, get_vehicle_depreciation_limits), so an agent must rely on domain knowledge of Section 179 vs. bonus depreciation to route correctly.

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 domain and by the year coverage stated (2025-2026, with 2027 explicitly unavailable as of 2026-11-02), which is a useful boundary. But there is no explicit when-to-use / when-not guidance, no mention of the alternative depreciation tools, and no stated prerequisites such as needing the property placed in service in the year.

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 the tool as read-only, idempotent, non-destructive, and closed-world. The description adds substantial domain behavior: it explains the GVWR bands, year-specific caps, bonus depreciation treatment, and business-use scaling. It does not describe the return structure, but the annotations carry the safety profile.

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 core purpose and then supplies dense, relevant detail. It is a long run-on sentence, but every clause contributes useful tax-rule context 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?

For a read-only lookup tool with a fully described schema, the description is largely complete: it covers the key thresholds, years, caps, and business-use rule. Because there is no output schema, it could say more about the return shape, but the core behavior is sufficiently explained.

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 all six parameters. The description adds meaning beyond the schema by mapping GVWR ranges to specific cap regimes and by explaining how tax year, bonus eligibility, exempt status, and business use affect the result. It does not mention the cost parameter, but the schema covers it.

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 states a specific verb and resource: it returns first-year write-off limits for a business vehicle by GVWR. It is clear what the tool does, but it does not explicitly distinguish itself from sibling calculation tools such as calculate_section_179 or calculate_bonus_depreciation.

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 GVWR thresholds and the business-use rule, but the description does not say when to use this tool versus the sibling calculation tools. It also does not state exclusions or prerequisites beyond the more-than-50% business use rule.

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