# magent CHIP Rule Calculator (Smits 2007) > magent CHIP Rule Calculator (Smits 2007) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14). Applies the Smits 2007 CHIP clinical decision rule to determine whether an adult minor head injury patient warrants a CT scan based on major and minor criteria ## Facts - Endpoint: GET https://api.magentlab.com/api/calc/chip - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-09-14 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/magent-chip-rule-calculator-smits-2007-b1c88e89 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_58zmxpbQ3z5PwBlvQDQOZ Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability magent-chip-rule-calculator-smits-2007-b1c88e89 ``` Example prompt: Apply the Smits 2007 CHIP rule to a 58-year-old patient with GCS 14, vomiting once, no anticoagulants, no seizure, was a pedestrian hit by a car, has posttraumatic amnesia lasting about 3 hours, no skull contusion, no neurologic deficit, no loss of consciousness, and no GCS deterioration at 1 hour — should they get a CT? ## When to prefer this Use this endpoint when you need to apply the specific Smits 2007 CHIP rule for adults (≥16) with minor head injury (GCS 13–15) and want a structured, auditable decision-support output. Prefer this over the Canadian CT Head Rule, NEXUS Head, or PECARN endpoints when the clinical context is adult minor TBI and the Smits 2007 criteria are indicated. This endpoint is purely computational — it does not examine patients or gather clinical data; the caller must supply all pre-assessed values. ## Known failure modes - Missing required query parameters (age, GCS, or any boolean criterion) returns a 400 error - Age below 16 or GCS outside 13–15 may produce an error or undefined behavior as the rule only applies to adults with minor head injury - Mutually exclusive pta_ge_4h and pta_2_to_lt_4h both set to true may produce an error or unreliable result - Payment not included or insufficient USDC balance returns a 402 Payment Required response - GCS value outside integer range 13–15 will be rejected as invalid per the published rule ## How this service works Smits 2007 CHIP rule (adults ≥16, GCS 13-15). CT if ≥1 major (pedestrian/cyclist vs vehicle, ejected, vomiting, PTA ≥4 h, skull-fracture signs, GCS <15, GCS drop ≥2 at 1 h, anticoagulants, posttraumatic seizure, age ≥60) or ≥2 minor (fall from elevation, persistent anterograde amnesia, PTA 2 to <4 h, skull contusion, neurologic deficit, LOC, GCS drop of 1 at 1 h, age 40-60). Not a diagnosis; not Canadian CT Head, NEXUS, PECARN, or 2022 CHIP. magent does not examine the patient. ## Output Returns a structured result indicating whether CT imaging is recommended under the Smits 2007 CHIP rule, along with which major and minor criteria were met. The caller provides all clinical findings; the API applies the published decision logic and returns a CT-indicated true/false determination with criterion breakdown. ## Request schema (JSON Schema) ```json { "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "input" ], "properties": { "input": { "type": "object", "required": [ "type", "method" ], "properties": { "type": { "type": "string", "const": "http" }, "method": { "enum": [ "GET", "HEAD", "DELETE" ], "type": "string" }, "headers": { "type": "object", "additionalProperties": { "type": "string" } }, "queryParams": { "type": "object", "required": [ "age", "gcs", "pedestrian_or_cyclist_vs_vehicle", "ejected_from_vehicle", "vomiting", "pta_ge_4h", "clinical_signs_skull_fracture", "gcs_deterioration_ge_2", "anticoagulant_therapy", "posttraumatic_seizure", "fall_from_any_elevation", "persistent_anterograde_amnesia", "pta_2_to_lt_4h", "skull_contusion", "neurologic_deficit", "loss_of_consciousness", "gcs_deterioration_1" ], "properties": { "age": { "type": "integer", "description": "Age in years (integer 16-120). Age ≥60 is a major criterion. Age 40-59 is the 40-60 y minor band; 39 is neither. The published rule is for patients ≥16 years." }, "gcs": { "type": "integer", "description": "Glasgow Coma Scale integer 13-15 as published. GCS 13 or 14 (GCS <15) is a major criterion; 15 is not. magent does not assign GCS from an exam." }, "vomiting": { "type": "boolean", "description": "Vomiting (Smits 2007 major). true or false as assigned by the caller. magent does not take a vomit count." }, "pta_ge_4h": { "type": "boolean", "description": "Posttraumatic amnesia ≥4 hours (Smits 2007 major). true or false as assigned by the caller. Mutually exclusive with pta_2_to_lt_4h. magent does not measure amnesia duration." }, "pta_2_to_lt_4h": { "type": "boolean", "description": "Posttraumatic amnesia of 2 to <4 hours (Smits 2007 minor). true or false as assigned by the caller. Mutually exclusive with pta_ge_4h. magent does not measure amnesia duration." }, "skull_contusion": { "type": "boolean", "description": "Contusion of the skull (Smits 2007 minor). true or false as assigned by the caller. magent does not examine the scalp." }, "neurologic_deficit": { "type": "boolean", … (truncated) ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/magent-chip-rule-calculator-smits-2007-b1c88e89/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)