Lenz Fact-Check

Check usage & credits

check_usage

Read-only

Return the account's remaining Lenz credits, and what they still buy.

One pool funds every call. ``costs`` is the live price list — read the
weight from there rather than assuming one. ``verify_claim`` is the
expensive tool by an order of magnitude; ``assess_claim`` and
``ask_followup`` are the cheap ones.

``costs`` is keyed by capability at its default price. ``cost_options``
holds the prices that depend on a request parameter, nested capability →
parameter → value — today ``verify_claim`` at ``depth="low"``, under
``cost_options.verify.depth.low``. Read the low-depth price from there.

``assess_remaining`` and ``verify_remaining`` are two views of the SAME
balance, not separate allowances: spending on one reduces both. Call this
when the user asks about credits, or before a large batch to size it
against ``credits_remaining``. It is not a prerequisite: never call it
before an ordinary check. ``next`` is one example of what the user can ask.

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 6, 2026

TDQS

A4.6/5.0

Behavior4/5

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

Annotations already establish read-only, non-destructive, closed-world, so the bar is coverage of semantics. The description adds genuinely useful behavior: assess_remaining and verify_remaining are two views of ONE balance, spending on one reduces both, and verify_claim costs an order of magnitude more than assess_claim/ask_followup. It does not mention rate limits or failure modes, keeping it short of a 5.

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

Conciseness4/5

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

Front-loaded with the core purpose, and each paragraph earns its place by resolving a real ambiguity (shared balance, price list location, cost ordering). It is slightly long and burdened with escaped/doubled backticks around field names, which is structure noise rather than substance.

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

Completeness5/5

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

With an output schema present, the description needn't enumerate return values, yet it still explains the non-obvious shape of costs/cost_options and the shared-balance trap. Combined with annotations covering safety, an agent has everything needed to call and interpret this correctly.

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

Parameters4/5

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

Zero input parameters, so the baseline of 4 applies. The description instead explains the returned pricing structure (costs keyed by capability, cost_options nested by parameter/value), which is output-side guidance rather than parameter semantics; no input semantics exist to clarify.

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?

Opens with a specific verb+resource+scope: 'Return the account's remaining Lenz credits, and what they still buy.' It immediately separates itself from the verification siblings by naming the pricing surfaces (costs, cost_options) it's the entry point to.

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

Usage Guidelines5/5

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

Explicitly states when to call ('when the user asks about credits, or before a large batch to size it') and, unusually, when NOT to ('It is not a prerequisite: never call it before an ordinary check'). It also routes the agent to costs/cost_options for pricing rather than guessing weights.

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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