FreshProof

verify_url

Read-only

Verify what is observable at a public URL before an agent trusts, pays, or acts. This paid tool combines observe_url and verify_proof in one call: it buys an observation, creates or returns a Proof Receipt, and evaluates the supplied trust policy. Set max_age=0 when current public-network evidence is required. The result contains both observation evidence and verification with decision PASS, FAIL, or UNKNOWN.

Input Schema

TableJSON Schema

Name	Required	Description
`url`	Yes	Public HTTP or HTTPS URL to observe and verify.
`policy`	Yes	Declarative trust policy evaluated against the resulting Proof Receipt.
`max_age`	No	Maximum acceptable observation age in seconds. Defaults to 300. Set to 0 to require a fresh public-network request before policy evaluation.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`observation`	Yes
`verification`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed11 schema fields changedSep 29, 2026

addedInput schema / properties / max_age / description

Added value: +"Maximum acceptable observation age in seconds. Defaults to 300. Set to 0 to require a fresh public-network request before policy evaluation."

changedInput schema / properties / policy / description

Previous value: -"Declarative policy evaluated against the resulting proof"New value: +"Declarative trust policy evaluated against the resulting Proof Receipt."

addedInput schema / properties / policy / properties / changed_since_content_hash / description

Added value: +"Prior SHA-256 response-body fingerprint. Passes when the current proof has a different content hash."

addedInput schema / properties / policy / properties / content_hash_equals / description

Added value: +"Expected SHA-256 response-body fingerprint, including the sha256: prefix. Passes only on exact equality."

addedInput schema / properties / policy / properties / final_host_equals / description

Added value: +"Expected lowercase hostname after redirects, for example example.com. Provide a hostname, not a full URL."

addedInput schema / properties / policy / properties / max_age_seconds / description

Added value: +"Maximum allowed age of the stored observation in seconds at verification time."

addedInput schema / properties / policy / properties / original_host_equals / description

Added value: +"Expected lowercase hostname from the originally requested URL. Provide a hostname, not a full URL."

addedInput schema / properties / policy / properties / require_same_origin_redirect / description

Added value: +"When true, fails if the final URL origin differs from the original URL origin after redirects."

addedInput schema / properties / policy / properties / status_in / description

Added value: +"Allowed HTTP status codes. The rule passes when the observed status is in this list."

changedInput schema / properties / url / description

Previous value: -"Public HTTP or HTTPS URL to observe and verify"New value: +"Public HTTP or HTTPS URL to observe and verify."

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "observation": {
+      "additionalProperties": false,
+      "properties": {
+        "age_seconds": {
+          "maximum": 9007199254740991,
+          "minimum": 0,
+          "type": "integer"
+        },
+        "content_hash": {
+          "pattern": "^sha256:[a-f0-9]{64}$",
+          "type": "string"
+        },
+        "content_length": {
+          "maximum": 9007199254740991,
+          "minimum": 0,
+          "type": "integer"
+        },
+        "etag": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "fetch_duration_ms": {
+          "maximum": 9007199254740991,
+          "minimum": 0,
+          "type": "integer"
+        },
+        "final_url": {
+          "format": "uri",
+          "type": "string"
+        },
+        "last_modified": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "observed_at": {
+          "description": "ISO-8601 timestamp of the observation.",
+          "type": "string"
+        },
+        "proof_id": {
+          "description": "FreshProof proof identifier returned by observe_url or verify_url.",
+          "pattern": "^fp1_[a-f0-9]{64}$",
+          "type": "string"
+        },
+        "receipt_hash": {
+          "pattern": "^sha256:[a-f0-9]{64}$",
+          "type": "string"
+        },
+        "source": {
+          "description": "fresh_fetch means FreshProof made a new public-network request; shared_cache means a stored observation satisfied max_age.",
+          "enum": [
+            "shared_cache",
+            "fresh_fetch"
+          ],
+          "type": "string"
+        },
+        "status": {
+          "maximum": 599,
+          "minimum": 100,
+          "type": "integer"
+        },
+        "url": {
+          "format": "uri",
+          "type": "string"
+        }
+      },
+      "required": [
+        "url",
+        "final_url",
+        "observed_at",
+        "age_seconds",
+        "status",
+        "content_hash",
+        "content_length",
+        "etag",
+        "last_modified",
+        "fetch_duration_ms",
+        "source",
+        "proof_id",
+        "receipt_hash"
+      ],
+      "type": "object"
+    },
+    "verification": {
+      "additionalProperties": false,
+      "properties": {
+        "checks": {
+          "items": {
+            "additionalProperties": false,
+            "properties": {
+              "actual": {
+                "description": "Observed value used by the rule."
+              },
+              "expected": {
+                "description": "Expected value or condition used by the rule."
+              },
+              "pass": {
+                "description": "Whether this individual rule passed.",
+                "type": "boolean"
+              },
+              "rule": {
+                "description": "Policy rule that was evaluated.",
+                "type": "string"
+              }
+            },
+            "required": [
+              "rule",
+              "pass",
+              "actual",
+              "expected"
+            ],
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "decision": {
+          "description": "Overall policy decision. PASS means every supplied rule passed; FAIL means at least one supplied rule failed; UNKNOWN means a reliable decision could not be made.",
+          "enum": [
+            "PASS",
+            "FAIL",
+            "UNKNOWN"
+          ],
+          "type": "string"
+        },
+        "proof_id": {
+          "description": "FreshProof proof identifier returned by observe_url or verify_url.",
+          "pattern": "^fp1_[a-f0-9]{64}$",
+          "type": "string"
+        },
+        "receipt": {
+          "additionalProperties": false,
+          "properties": {
+            "payload": {
+              "additionalProperties": false,
+              "properties": {
+                "content_hash": {
+                  "pattern": "^sha256:[a-f0-9]{64}$",
+                  "type": "string"
+                },
+                "content_length": {
+                  "maximum": 9007199254740991,
+                  "minimum": 0,
+                  "type": "integer"
+                },
+                "etag": {
+                  "type": [
+                    "string",
+                    "null"
+                  ]
+                },
+                "fetch_duration_ms": {
+                  "maximum": 9007199254740991,
+                  "minimum": 0,
+                  "type": "integer"
+                },
+                "final_url": {
+                  "format": "uri",
+                  "type": "string"
+                },
+                "last_modified": {
+                  "type": [
+                    "string",
+                    "null"
+                  ]
+                },
+                "method": {
+                  "const": "GET",
+                  "type": "string"
+                },
+                "normalized_url": {
+                  "format": "uri",
+                  "type": "string"
+                },
+                "observation_id": {
+                  "type": "string"
+                },
+                "observed_at": {
+                  "description": "ISO-8601 timestamp of the observation.",
+                  "type": "string"
+                },
+                "original_url": {
+                  "format": "uri",
+                  "type": "string"
+                },
+                "status": {
+                  "maximum": 599,
+                  "minimum": 100,
+                  "type": "integer"
+                },
+                "version": {
+                  "const": "freshproof-receipt-v1",
+                  "type": "string"
+                }
+              },
+              "required": [
+                "version",
+                "observation_id",
+                "normalized_url",
+                "original_url",
+                "final_url",
+                "observed_at",
+                "method",
+                "status",
+                "content_hash",
+                "content_length",
+                "etag",
+                "last_modified",
+                "fetch_duration_ms"
+              ],
+              "type": "object"
+            },
+            "proof_id": {
+              "description": "FreshProof proof identifier returned by observe_url or verify_url.",
+              "pattern": "^fp1_[a-f0-9]{64}$",
+              "type": "string"
+            },
+            "receipt_hash": {
+              "description": "SHA-256 content address of the canonical Proof Receipt payload.",
+              "pattern": "^sha256:[a-f0-9]{64}$",
+              "type": "string"
+            }
+          },
+          "required": [
+            "proof_id",
+            "receipt_hash",
+            "payload"
+          ],
+          "type": "object"
+        },
+        "valid": {
+          "description": "True when the stored receipt passes deterministic integrity verification.",
+          "type": "boolean"
+        }
+      },
+      "required": [
+        "proof_id",
+        "valid",
+        "decision",
+        "checks",
+        "receipt"
+      ],
+      "type": "object"
+    }
+  },
+  "required": [
+    "observation",
+    "verification"
+  ],
+  "type": "object"
+}

AddedSep 28, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Goes well beyond the annotations by disclosing that the call is paid, that it buys an observation and creates or returns a Proof Receipt, and that the decision space is PASS/FAIL/UNKNOWN. The remaining gap is that the advertised purchase/receipt-creation side effect is not reconciled with readOnlyHint=true, leaving a small ambiguity about exactly what state the call mutates.

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?

Four sentences, purpose front-loaded, then mechanism, then a parameter tip, then the result shape. Tight overall, though the max_age=0 guidance partially duplicates the schema description, which is the one sentence that does not fully earn its place.

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

Completeness4/5

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

For a paid, open-world, non-idempotent tool with a nested policy object, the description covers cost, mechanism, freshness semantics, and decision vocabulary; an output schema exists so return shape needs no further detail. It does not mention authorization or pricing model, but nothing essential for correct invocation is missing.

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

Parameters3/5

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

Schema coverage is 100% and the schema already documents url, policy, and every policy sub-rule in detail, including the max_age default of 300 and the meaning of max_age=0. The description largely restates this ('evaluates the supplied trust policy', 'Set max_age=0'), so it adds little meaning beyond the structured fields.

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?

States a specific verb+resource ('Verify what is observable at a public URL') and immediately frames the scope. It explicitly positions itself against siblings by naming observe_url and verify_proof and describing the combination ('combines observe_url and verify_proof in one call'), so an agent can distinguish it without opening the schema.

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

Usage Guidelines4/5

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

Gives a clear operating context ('before an agent trusts, pays, or acts') and one concrete condition ('Set max_age=0 when current public-network evidence is required'). The implication that this replaces calling observe_url and verify_proof separately is strong but not stated as an explicit when-to-use rule or exclusion, so it falls short of a 5.

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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