opentax

find_tax_cliffs

Find exact dollar amounts where one more cent of an input costs MORE than a cent of tax (marginal rate over 100%) — e.g. the EITC investment-income kill switch, CTC phase-out steps. Every probe is a real evaluation.

Input Schema

TableJSON Schema

Name	Required	Description
`vary`	Yes	money fact to vary, e.g. "wages" or "taxableInterest"
`facts`	Yes	facts for the computation: either flat corpus fact ids (see list_input_facts) or the same group objects calculate_tax accepts (filing, income, retirement, …), plus optional target and asOf. Business/fiduciary/dependent facts are accepted flat. Unknown keys are rejected by name — nothing is ever silently dropped.
`toDollars`	Yes
`fromDollars`	Yes
`stepDollars`	No	coarse scan step, default 1000

TDQS

B3.3/5.0

Behavior2/5

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

No annotations are provided. The description mentions 'every probe is a real evaluation,' suggesting actual tax calculations, but does not disclose performance, side effects, authentication needs, or rate limits. Lacks rich behavioral context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence with a parenthetical, no fluff, and front-loads the core purpose. Every word adds value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no output schema and moderate complexity, the description fails to explain what the tool returns, how the facts object is structured, or the scanning logic beyond 'real evaluation.' Incomplete for agent to invoke correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 60%, but the tool description adds no additional meaning beyond schema. The parameters (vary, facts, fromDollars, toDollars, stepDollars) are not elaborated. For example, stepDollars default is only in schema. Description does not compensate for uncovered parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool finds exact dollar amounts where marginal tax rate exceeds 100% (tax cliffs), with specific examples like EITC and CTC. It distinctively identifies unique functionality among siblings, which are mostly calculation or fact tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage for finding tax cliffs but provides no explicit guidance on when to use or avoid this tool versus alternatives like calculate_tax or search_tax_rules. No when-not-to guidelines.

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

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TDQS

A4.1/5.0

Disambiguation5/5

Each tool has a clearly distinct purpose: calculate_tax handles individuals, calculate_business_tax handles entities, calculate_fiduciary_tax handles estates/trusts, compute_return produces the complete federal return, compute_state_return handles state returns, and the remaining tools cover specific lookups (parameters, rules, facts, dependencies, cliffs, tipped occupations) or verification. Even with overlapping domains (explain_rule, lookup_tax_parameter, search_tax_rules, verify_fact, verify_tax_claim), their roles are sharply delineated.

Naming Consistency4/5

Tool names follow a clear pattern: compute_return, compute_state_return, calculate_tax, calculate_business_tax, calculate_fiduciary_tax, determine_dependent, explain_rule, find_tax_cliffs, is_tipped_occupation, list_input_facts, lookup_tax_parameter, search_tax_rules, verify_fact, verify_tax_claim. Most use verb_noun (calculate_tax, lookup_tax_parameter, search_tax_rules, verify_fact). Minor deviations: compare_filing_statuses and compute_return use adjective/noun phrases rather than verb_noun, but they're still readable and follow the 'compute/calculate' theme.

Tool Count5/5

15 tools is well-scoped for a comprehensive tax computation server. Each tool covers a distinct aspect of tax law (federal individual, business, fiduciary, state returns, dependency, rule lookup, parameter lookup, validation, cliff detection, fact verification, search). No tool feels redundant, and the count supports the ambitious scope without bloating.

Completeness5/5

The tool surface covers the full tax workflow: input discovery (list_input_facts), computation (calculate_tax, calculate_business_tax, calculate_fiduciary_tax, compute_return, compute_state_return), dependency determination (determine_dependent), rule/parameter lookup (explain_rule, lookup_tax_parameter, search_tax_rules), verification (verify_fact, verify_tax_claim), and specialized analysis (find_tax_cliffs, is_tipped_occupation, compare_filing_statuses). There's no obvious gap; the only potential missing feature is payroll tax computation, but that's outside the stated domain of income tax.

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