US Sales Tax Economic Nexus Check

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

No annotations exist, so the description carries the full behavioral burden and does substantial work: it categorizes returns (over threshold, 80%+ near threshold, under), explains the SAFE-answer fallback for unclear cases and that it discloses the dependency, and notes 'Free'. It does not explicitly state the tool is read-only/no side effects, but the framing implies a pure computation. Strong disclosure overall.

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, which is good, but the body is one very dense run-on paragraph that crams the entire output taxonomy into long comma-separated lists. Every clause is arguably relevant, but the structure hurts scannability for a description this size.

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?

There is no output schema, so the description must explain returns, and it does, thoroughly: the four state buckets plus per-state threshold, measurement period, what sales count, marketplace treatment, registration timing and source. Combined with a fully documented schema for a genuinely complex domain, an agent has what it needs; only the read-only/no-side-effect nature and date-rule semantics are left implicit.

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 five parameters including the enum, defaults and nested item shape. The description adds only marginal meaning (marketplace-inclusion rationale: 'Many states exclude those sales when testing a remote seller's threshold') and does not explain the date parameter's rule-versioning behavior, which the schema itself covers. Baseline 3 is appropriate.

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: checks which US states a remote seller must register in for sales tax, from its sales by state. The scope is narrow and concrete enough that it is clearly distinguishable from siblings like list_nexus_thresholds (generic threshold reference) and list_upcoming_nexus_changes, even without naming them.

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?

It tells the agent what data to supply ('Give sales_by_state with the dollar sales and number of transactions... and whether they include marketplaces') which implies the usage context, but never states when to use this tool versus list_nexus_thresholds or list_upcoming_nexus_changes, and gives no exclusions or prerequisites. Usage is inferred rather than guided.

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?

With no annotations, the description carries the full burden. It does add useful traits: it is a zero-parameter read of metadata, discloses the 'Free' cost profile, and lists the returned content. It omits any auth requirement or freshness caveats beyond the last-checked date. Adequate but not rich for an annotation-free 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?

A single tight sentence that front-loads the resource and packs coverage figures, freshness, related servers, and cost with zero waste.

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 zero-param, no-annotation tool with no output schema, the description adequately conveys what comes back and that it is free. Only minor gaps remain, such as auth or rate-limit context, which are low risk for a metadata read.

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?

The tool takes zero parameters, so the baseline is 4. The description correctly reinforces that this is an unfiltered listing, adding no misleading parameter expectations.

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 (Lists) and enumerates exactly what is returned: coverage details, last-checked date, and related Rules servers. This clearly distinguishes it from the nexus-specific siblings, though it does not name them explicitly.

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?

No statement of when to call this tool versus the nexus tools, no prerequisites, and no exclusions. The only usage-relevant hint is the trailing 'Free', which implies no cost but does not guide invocation timing.

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?

No annotations exist, so the description carries the full burden, and it does reasonably well: 'Lists' implies a read-only operation, 'on a date' signals point-in-time, as-of-date semantics, and 'Free' discloses cost behavior. It stops short of describing response structure or any rate/limit behavior, which for a bounded 50-state list is minor.

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 verb+resource, and the extra clauses (no-tax states, 'Free') are informative rather than padding. The first sentence is a long run-on enumeration, which slightly hurts scannability.

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 and no annotations, the description compensates by enumerating the returned fields (thresholds, logic, measurement period, marketplace rules, registration timing, official source) and the no-statewide-tax states. That is essentially complete for a reference-list tool, though it never states the shape of the response.

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 already 100%, so the baseline is 3. The phrase '(or one state) on a date' reinforces the state and date parameters and hints at as-of-date threshold semantics, but adds little beyond what the schema properties already say.

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 ('Lists') and resource ('economic nexus threshold of every US sales tax state'), with rich detail on what the listing contains. It does not, however, draw an explicit contrast with the sibling check_economic_nexus, so an agent must infer that this is a reference lookup rather than a per-business check.

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 content (reference lookup of state thresholds), and the optional state narrowing is noted, but there is no explicit when-to-use guidance, no when-not-to-use, and no reference to the alternatives check_economic_nexus or list_upcoming_nexus_changes.

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?

With no annotations, the description carries the burden and does disclose return content (old and new rule plus source), result ordering, and cost ('Free'). It does not mention any cap on result count, pagination, or what happens at the edge of the 1460-day limit, which are the remaining behavioral unknowns.

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?

Two sentences with the core purpose front-loaded, followed by the one usage hint and the cost note. No filler and no repetition of the schema.

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?

No output schema exists, and the description compensates by naming the returned fields and ordering. For a two-optional-parameter read tool this is nearly complete, missing only result-size or pagination expectations.

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 both parameters are already documented with ranges and defaults, establishing a baseline of 3. The description adds only marginal meaning ('date window', the past-from_date hint) without clarifying how days and from_date combine into a window.

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 economic nexus threshold changes') plus the scope (date window), ordering (soonest first), and payload (old and new rule and source). The 'changes' framing implies a distinction from the sibling list_nexus_thresholds, but it never names an alternative outright to make the separation unambiguous.

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 one concrete usage cue: 'Use a past from_date to see recent changes.' There is no guidance on when to prefer this over list_nexus_thresholds or check_economic_nexus, and no statement of when not to use it, so usage remains largely inferred.

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