DiffiCat

Discover pages

discover_pages

Free 5 times a day per client address (at most 50 pages each), no key needed. Lists the pages of Site A (sitemap, robots.txt or crawl), mapped onto Site B when given. Call it to see which pages a comparison would cover or to pick pairs for urls. Do not call it before start_comparison only to price a job: a job without urls discovers for itself. Lists at most maxPages pages, 500 without it (up to 5000 when paid); truncated: true means the ceiling cut the list. Example: { "sourceUrl": "https://old.example", "targetUrl": "https://new.example", "maxPages": 50 }. Answers with pages (sourceUrl, targetUrl, path), strategy, truncated and, on a free run, sample and allowanceRemaining.

Input Schema

TableJSON Schema

Name	Required	Description
`maxPages`	No	Stop after this many pages (default and at most 5000).
`sourceUrl`	Yes	Site A (full URL).
`targetUrl`	No	Site B; pages are mapped onto it when given.
`sitemapUrl`	No	Sitemap to read instead of the fallbacks.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`code`	No
`error`	No
`pages`	No
`sample`	No
`payment`	No
`strategy`	No
`truncated`	No
`allowanceRemaining`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedOct 4, 2026

addedOutput schema / properties / allowanceRemaining

Added value: +{
+  "maximum": 9007199254740991,
+  "minimum": -9007199254740991,
+  "type": "integer"
+}

addedOutput schema / properties / sample
```
Added value: +{
+  "type": "boolean"
+}
```

Changed1 schema field changedOct 4, 2026
- addedOutput schema / properties / truncated
```
Added value: +{
+  "type": "boolean"
+}
```

Changed2 schema fields changedOct 4, 2026

changedInput schema / properties / maxPages / description

Previous value: -"Stop after this many pages."New value: +"Stop after this many pages (default and at most 5000)."

changedInput schema / properties / maxPages / maximum

Previous value: -9007199254740991New value: +5000

Changed5 schema fields changedOct 2, 2026

removedOutput schema / properties / payment / additionalProperties
```
Removed value: -false
```

addedOutput schema / properties / payment / anyOf

Added value: +[
+  {
+    "additionalProperties": false,
+    "properties": {
+      "amount": {
+        "type": "string"
+      },
+      "balance": {
+        "type": "string"
+      },
+      "currency": {
+        "const": "USD",
+        "type": "string"
+      },
+      "rail": {
+        "const": "prepaid",
+        "type": "string"
+      }
+    },
+    "required": [
+      "amount",
+      "currency",
+      "rail",
+      "balance"
+    ],
+    "type": "object"
+  },
+  {
+    "additionalProperties": false,
+    "properties": {
+      "allowanceRemaining": {
+        "type": "number"
+      },
+      "amount": {
+        "type": "string"
+      },
+      "currency": {
+        "const": "USD",
+        "type": "string"
+      },
+      "pagesFromAllowance": {
+        "type": "number"
+      },
+      "rail": {
+        "const": "subscription",
+        "type": "string"
+      }
+    },
+    "required": [
+      "amount",
+      "currency",
+      "rail",
+      "pagesFromAllowance",
+      "allowanceRemaining"
+    ],
+    "type": "object"
+  }
+]

removedOutput schema / properties / payment / properties

Removed value: -{
-  "amount": {
-    "type": "string"
-  },
-  "balance": {
-    "type": "string"
-  },
-  "currency": {
-    "const": "USD",
-    "type": "string"
-  },
-  "rail": {
-    "const": "prepaid",
-    "type": "string"
-  }
-}

removedOutput schema / properties / payment / required

Removed value: -[
-  "amount",
-  "currency",
-  "rail",
-  "balance"
-]

removedOutput schema / properties / payment / type
```
Removed value: -"object"
```

Changed1 schema field changedSep 29, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "code": {
+      "type": "string"
+    },
+    "error": {
+      "type": "string"
+    },
+    "pages": {
+      "items": {
+        "additionalProperties": false,
+        "properties": {
+          "path": {
+            "type": "string"
+          },
+          "sourceUrl": {
+            "type": "string"
+          },
+          "targetUrl": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "sourceUrl",
+          "path"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "payment": {
+      "additionalProperties": false,
+      "properties": {
+        "amount": {
+          "type": "string"
+        },
+        "balance": {
+          "type": "string"
+        },
+        "currency": {
+          "const": "USD",
+          "type": "string"
+        },
+        "rail": {
+          "const": "prepaid",
+          "type": "string"
+        }
+      },
+      "required": [
+        "amount",
+        "currency",
+        "rail",
+        "balance"
+      ],
+      "type": "object"
+    },
+    "strategy": {
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

Changed1 schema field changedSep 26, 2026
- changedInput schema / properties / maxPages / maximum
```
Previous value: -500New value: +9007199254740991
```
First observedSep 25, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Beyond the annotations, it discloses rate limits and quota ('Free 5 times a day per client address (at most 50 pages each), no key needed'), paid ceilings (up to 5000), truncation semantics ('truncated: true means the ceiling cut the list'), and the allowanceRemaining field. These are operational constraints an agent cannot get from readOnlyHint/openWorldHint alone.

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?

Dense but well front-loaded: quota/access first, then purpose, then usage constraints, then limits, then the response shape. Each sentence carries distinct information, though the middle section is a run-on that could be split for readability.

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?

An output schema exists, so return values need not be spelled out, yet the description still summarizes them (pages, strategy, truncated, sample, allowanceRemaining). Combined with quota, truncation, and usage routing, nothing an agent needs to invoke this correctly is missing.

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 the baseline is 3, but the description adds meaning the schema lacks: the default of 500 pages on a free run and the 5000 paid ceiling, plus how targetUrl mapping works. The example call also shows the three main parameters in combination, which aids correct invocation.

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 and resource ('Lists the pages of Site A (sitemap, robots.txt or crawl), mapped onto Site B'), and distinguishes itself from siblings by noting the difference from start_comparison and its role in picking pairs for urls. An agent can tell exactly what this tool returns and how it differs from compare_snapshot/start_comparison without opening any 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?

Gives explicit when-to-use ('to see which pages a comparison would cover or to pick pairs for urls') and an explicit when-not-to-use ('Do not call it before start_comparison only to price a job: a job without urls discovers for itself'). The alternative behavior is named rather than implied, which is the strongest form of routing guidance.

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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