What one model costs per month at a given token volume, in USD and KRW. Token prices are per million and hard to reason about directly; this turns them into a monthly bill. Input and output are mixed 75/25 unless you pass your own split.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | OpenRouter id or Hugging Face repo id | |
| inputShare | No | 0-1, share of tokens that are input. Default 0.75 | |
| monthlyMillionTokens | No | Default 10 |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the burden. It helpfully discloses the default 75/25 input/output mix and the monthly framing, but says nothing about required currency/permission context, error behavior for unknown ids, or what exactly is returned beyond 'USD and KRW'.
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?
Three front-loaded sentences that lead with the output and scope before the rationale. The middle sentence ('hard to reason about directly') is mildly chatty but earns its place by justifying the tool's existence.
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 simple calculation tool with 100% schema coverage and no output schema, the description supplies the key assumptions (default token volume, 75/25 mix, dual currency) an agent needs to call it correctly. Only edge-case or error behavior is unaddressed, which is minor here.
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 baseline is 3, but the description adds real meaning: it explains why inputShare exists ('Input and output are mixed 75/25 unless you pass your own split') and frames the monthly interpretation of monthlyMillionTokens, going beyond the raw schema text.
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 names a specific verb (estimate) and resource (monthly cost) and states the scope precisely: per model, at a given token volume, in USD and KRW. It clearly is the cost-estimation tool among price/model lookup siblings, though it never explicitly contrasts itself with get_price_history.
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 – pass a model id to turn per-million token prices into a monthly bill – but there is no explicit when-to-use/when-not guidance or routing to alternatives like get_price_history or compare_models. The 'unless you pass your own split' clause hints at an optional override but doesn't frame tool selection.
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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