FastGPU

Match a workload to the cheapest GPU

match_workload

Read-onlyIdempotent

Ranks up to eight GPU configurations that can run a job at the lowest live price. Describe the job in query (an open-weight model to serve or fine-tune, a model size, or a GPU need) or with the structured fields. Each match gives the GPU count, the USD per hour for the whole configuration and a one-line reason; the answer also states the VRAM the job needs and how much cheaper the top match is than a hyperscaler running the same job. Use it to decide where to run a workload; use list_gpu_prices for the price of a named GPU. Open-weight models only: an API-only model such as GPT-4 returns no matches and a note. Between otherwise equal offers, a small disclosed tie-break favors providers that pay FastGPU a referral (each match reports partner). Hard limits (budget_usd_hr, max_total_usd with duration_hours, max_quote_age_minutes) drop every configuration that breaks them; limits reports what was dropped. Read-only: it does not rent or launch GPUs. No key required.

Input Schema

Name	Required	Description
`spot`	No	Set true to include interruptible spot capacity for a cheaper rate.
`task`	No	What the job does.
`model`	No	Open model name to size against, e.g. "Llama 3 70B", "Qwen 72B", "Mixtral".
`query`	No	Plain-language job, e.g. "cheapest to serve Llama 3 70B", "2x H100 for fine-tuning" or "a GPU with 80GB of memory". Provide this OR a structured spec below.
`region`	No	Restrict to a data-residency region.
`vram_gb`	No	Rough VRAM the job needs, in GB, if you already know it.
`params_b`	No	Model size in billions of parameters when no exact model is named.
`reserved`	No	Set true to include reserved / committed-term capacity for a lower rate.
`gpu_count`	No	Exact positive GPU count. Overrides a count in query text. Returns no matches if no supported configuration fits; omit for automatic sizing.
`precision`	No	Numeric precision to size the model at.
`weights_gb`	No	Measured size of the weights as stored, in GB: the file you will load (for example a GGUF Q4_K_M build, which holds more bits per parameter than its nominal 4). Replaces parameters times bytes per parameter in the memory estimate. Used for a model sized by its parameter count; the answer's workload.weights_gb is null when it was not (an image or speech model sized as a whole pipeline).
`budget_usd_hr`	No	Hard limit on the hourly price of the whole configuration, in USD. Configurations above it are not returned.
`max_total_usd`	No	Hard limit on estimated_total_usd, the GPU rental cost of the whole job, in USD. Needs duration_hours. Configurations above it are not returned.
`duration_hours`	No	How long the job will run, in hours (fractions are fine). When sent, each match carries billed_hours and estimated_total_usd.
`min_gpu_memory_gb`	No	Memory each GPU card must have, in GB (e.g. 80 for 80GB-class cards such as the H100 or A100 80GB). Smaller cards are never returned. On its own it lists every card that size, cheapest first.
`max_quote_age_minutes`	No	Hard limit on how old a price quote may be, in minutes. Configurations whose price was fetched from the provider longer ago are not returned.

Output Schema

Name	Required	Description
`hero`	No
`note`	No	Why there are no matches, when there are none.
`as_of`	No	When this answer was computed (ISO 8601). Quote ages are measured against it.
`count`	Yes
`error`	No	Present when the request was not valid; says what to send instead.
`stale`	No
`limits`	No	The hard limits this answer applied (null when one was not sent) and how many configurations each one left out.
`matches`	Yes
`workload`	No
`updated_at`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 11, 2026

addedInput schema / properties / weights_gb

Added value: +{
+  "description": "Measured size of the weights as stored, in GB: the file you will load (for example a GGUF Q4_K_M build, which holds more bits per parameter than its nominal 4). Replaces parameters times bytes per parameter in the memory estimate. Used for a model sized by its parameter count; the answer's workload.weights_gb is null when it was not (an image or speech model sized as a whole pipeline).",
+  "type": "number"
+}

Changed14 schema fields changedOct 4, 2026

changedInput schema / properties / budget_usd_hr / description

Previous value: -"Only recommend configs at or under this hourly budget."New value: +"Hard limit on the hourly price of the whole configuration, in USD. Configurations above it are not returned."

addedInput schema / properties / duration_hours

Added value: +{
+  "description": "How long the job will run, in hours (fractions are fine). When sent, each match carries billed_hours and estimated_total_usd.",
+  "type": "number"
+}

addedInput schema / properties / max_quote_age_minutes

Added value: +{
+  "description": "Hard limit on how old a price quote may be, in minutes. Configurations whose price was fetched from the provider longer ago are not returned.",
+  "type": "number"
+}

addedInput schema / properties / max_total_usd

Added value: +{
+  "description": "Hard limit on estimated_total_usd, the GPU rental cost of the whole job, in USD. Needs duration_hours. Configurations above it are not returned.",
+  "type": "number"
+}

addedOutput schema / properties / as_of

Added value: +{
+  "description": "When this answer was computed (ISO 8601). Quote ages are measured against it.",
+  "type": "string"
+}

addedOutput schema / properties / error

Added value: +{
+  "description": "Present when the request was not valid; says what to send instead.",
+  "type": "string"
+}

addedOutput schema / properties / limits

Added value: +{
+  "description": "The hard limits this answer applied (null when one was not sent) and how many configurations each one left out.",
+  "properties": {
+    "budget_usd_hr": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "duration_hours": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "excluded": {
+      "properties": {
+        "older_than_max_quote_age_minutes": {
+          "type": "integer"
+        },
+        "over_budget_usd_hr": {
+          "type": "integer"
+        },
+        "over_max_total_usd": {
+          "type": "integer"
+        }
+      },
+      "type": "object"
+    },
+    "max_quote_age_minutes": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "max_total_usd": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "nearest_excluded": {
+      "description": "When the limits leave no match: the cheapest configuration that can still run the job, and the limits it breaks.",
+      "properties": {
+        "billed_hours": {
+          "description": "Hours the provider bills for duration_hours: rounded up to whole hours on a per-hour meter and to whole minutes on a per-minute meter. Null when duration_hours was not sent.",
+          "type": [
+            "number",
+            "null"
+          ]
+        },
+        "billing_increment": {
+          "description": "How this provider's meter ticks for on-demand rental; varies means FastGPU has no verified figure.",
+          "enum": [
+            "per-second",
+            "per-minute",
+            "per-hour",
+            "varies"
+          ],
+          "type": "string"
+        },
+        "breaks": {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        "effective_usd_hr": {
+          "type": "number"
+        },
+        "estimated_total_usd": {
+          "description": "effective_usd_hr times billed_hours, rounded up to the cent. GPU rental only: storage, data transfer, CPU and memory billed separately, and provider minimums are not included. Null when duration_hours was not sent.",
+          "type": [
+            "number",
+            "null"
+          ]
+        },
+        "fetched_at": {
+          "description": "When this price was fetched from the provider (ISO 8601).",
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "fits_single_card": {
+          "type": "boolean"
+        },
+        "gpu": {
+          "type": "string"
+        },
+        "gpu_count": {
+          "type": "integer"
+        },
+        "monthly_usd": {
+          "type": "number"
+        },
+        "offer_type": {
+          "type": "string"
+        },
+        "over_budget": {
+          "type": "boolean"
+        },
+        "page_url": {
+          "description": "Absolute URL of this GPU's live price page, with every live offer.",
+          "type": "string"
+        },
+        "partner": {
+          "type": "boolean"
+        },
+        "provider": {
+          "type": "string"
+        },
+        "provider_label": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "quote_age_seconds": {
+          "description": "Seconds between fetched_at and as_of. Null when the fetch time is unknown.",
+          "type": [
+            "integer",
+            "null"
+          ]
+        },
+        "reason": {
+          "type": "string"
+        },
+        "reliability": {
+          "type": "string"
+        },
+        "score": {
+          "type": [
+            "number",
+            "null"
+          ]
+        },
+        "tokens_per_sec": {
+          "type": [
+            "number",
+            "null"
+          ]
+        },
+        "url": {
+          "description": "Site-relative path of this GPU's live price page, e.g. /gpus/h100-sxm.",
+          "type": "string"
+        },
+        "usd_per_million_tokens": {
+          "type": [
+            "number",
+            "null"
+          ]
+        }
+      },
+      "type": [
+        "object",
+        "null"
+      ]
+    }
+  },
+  "type": "object"
+}

addedOutput schema / properties / matches / items / properties / billed_hours

Added value: +{
+  "description": "Hours the provider bills for duration_hours: rounded up to whole hours on a per-hour meter and to whole minutes on a per-minute meter. Null when duration_hours was not sent.",
+  "type": [
+    "number",
+    "null"
+  ]
+}

addedOutput schema / properties / matches / items / properties / billing_increment

Added value: +{
+  "description": "How this provider's meter ticks for on-demand rental; varies means FastGPU has no verified figure.",
+  "enum": [
+    "per-second",
+    "per-minute",
+    "per-hour",
+    "varies"
+  ],
+  "type": "string"
+}

addedOutput schema / properties / matches / items / properties / estimated_total_usd

Added value: +{
+  "description": "effective_usd_hr times billed_hours, rounded up to the cent. GPU rental only: storage, data transfer, CPU and memory billed separately, and provider minimums are not included. Null when duration_hours was not sent.",
+  "type": [
+    "number",
+    "null"
+  ]
+}

addedOutput schema / properties / matches / items / properties / fetched_at

Added value: +{
+  "description": "When this price was fetched from the provider (ISO 8601).",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / matches / items / properties / quote_age_seconds

Added value: +{
+  "description": "Seconds between fetched_at and as_of. Null when the fetch time is unknown.",
+  "type": [
+    "integer",
+    "null"
+  ]
+}

addedOutput schema / properties / note

Added value: +{
+  "description": "Why there are no matches, when there are none.",
+  "type": "string"
+}

addedOutput schema / properties / workload / properties / gpu_vendors

Added value: +{
+  "items": {
+    "type": "string"
+  },
+  "type": [
+    "array",
+    "null"
+  ]
+}

Changed3 schema fields changedOct 1, 2026

addedInput schema / properties / min_gpu_memory_gb

Added value: +{
+  "description": "Memory each GPU card must have, in GB (e.g. 80 for 80GB-class cards such as the H100 or A100 80GB). Smaller cards are never returned. On its own it lists every card that size, cheapest first.",
+  "type": "integer"
+}

changedInput schema / properties / query / description

Previous value: -"Plain-language job, e.g. \"cheapest to serve Llama 3 70B\" or \"2x H100 for fine-tuning\". Provide this OR a structured spec below."New value: +"Plain-language job, e.g. \"cheapest to serve Llama 3 70B\", \"2x H100 for fine-tuning\" or \"a GPU with 80GB of memory\". Provide this OR a structured spec below."

addedOutput schema / properties / workload / properties / min_gpu_memory_gb
```
Added value: +{
+  "type": [
+    "integer",
+    "null"
+  ]
+}
```

Changed2 schema fields changedSep 30, 2026

addedOutput schema / properties / matches / items / properties / page_url

Added value: +{
+  "description": "Absolute URL of this GPU's live price page, with every live offer.",
+  "type": "string"
+}

addedOutput schema / properties / matches / items / properties / url / description

Added value: +"Site-relative path of this GPU's live price page, e.g. /gpus/h100-sxm."

Changed2 schema fields changedSep 11, 2026

changedInput schema / properties / gpu_count / description

Previous value: -"Force a specific GPU count instead of letting the engine size it."New value: +"Exact positive GPU count. Overrides a count in query text. Returns no matches if no supported configuration fits; omit for automatic sizing."

addedOutput schema / properties / workload / properties / gpu_count

Added value: +{
+  "type": [
+    "integer",
+    "null"
+  ]
+}

First observedSep 1, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Reveals behavior beyond annotations: tie-break favoring referral-paying providers, hard-limit filtering with 'limits' reporting dropped configs, API-only models returning no matches, and explicit read-only/no-rental statement. Rich disclosure not present in structured fields.

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 core outcome and helpful, though fairly dense across several sentences. Every sentence carries useful information, but the tie-break/partner disclosure is slightly buried.

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?

Despite 16 params and no required fields, the description covers both input modes, filtering behavior, output highlights, restrictions, and the read-only nature. Output schema exists so return fields need not be detailed; description still summarizes key outputs helpfully.

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?

Schema coverage is 100%, so baseline is 3. Description adds cross-parameter semantics: budget_usd_hr/max_total_usd/duration_hours/max_quote_age_minutes as hard limits that drop configs, and query-vs-structured precedence hints. Marginal added value over schema.

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?

Specific verb (ranks/ranks up to eight configurations) and resource (GPU configs at lowest live price) with explicit scope and a named sibling (list_gpu_prices) for a different task. An agent can distinguish it from list_gpu_prices without opening either schema.

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 'Use it to decide where to run a workload; use list_gpu_prices for the price of a named GPU.' Also explains the query-vs-structured-fields alternative input paths and open-weight-only restriction.

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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