Groundhog

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Read a URL

read_url

Read-only

Fetches a web page through a stealth browser and returns clean, citable content with provenance, stripping text hidden from human readers.

Instructions

Fetch one web page through the stealth browser and return clean, grounded content with provenance.

Hidden text injected for models but invisible to humans is stripped by default and reported in threats. Use this to ground answers in live web content, including sites that block plain fetchers.

Reads a URL you already have: use search to find URLs, or research to search and read in one call. Fetches are rate limited per domain (5s apart by default), so several pages from one site are not instant.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`url`	Yes	Absolute http(s) URL. Private and loopback addresses are refused.
`query`	No	When set, `matches` carries the passages most relevant to it, each with its heading and offset for citation.
`format`	No	'markdown' extracts the article; 'text' returns the page's rendered text.	markdown
`max_tokens`	No	Token budget for the content. Omit to use the server's GROUNDHOG_MAX_TOKENS (20000 by default). Must be positive.
`include_hidden`	No	Keep text that is invisible to a human reader. It is reported in `threats` either way; this only controls whether it stays in the content.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`url`	Yes
`title`	Yes
`status`	Yes
`matches`	Yes
`threats`	Yes
`markdown`	Yes
`final_url`	Yes
`truncated`	Yes
`fetched_at`	Yes
`provenance`	Yes
`http_status`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.15.0Sep 13, 2026
- addedOutput schema / $defs / Threat / properties / seen
```
Added value: +{
+  "title": "Seen",
+  "type": "integer"
+}
```

Changed1 schema field changedv0.13.0Sep 7, 2026

changedOutput schema / $defs / Threat / properties / type / enum

Previous value: -[
-  "hidden_css",
-  "report_truncated",
-  "final_url_suppressed",
-  "detection_degraded",
-  "strip_incomplete",
-  "zero_width",
-  "bidi",
-  "tag"
-]New value: +[
+  "hidden_css",
+  "hidden_attribute",
+  "hidden_template",
+  "report_truncated",
+  "final_url_suppressed",
+  "detection_degraded",
+  "strip_incomplete",
+  "zero_width",
+  "bidi",
+  "tag"
+]

Changed3 schema fields changedv0.10.0Aug 3, 2026

addedOutput schema / properties / http_status

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "title": "Http Status"
+}

addedOutput schema / properties / status

Added value: +{
+  "enum": [
+    "ok",
+    "challenge",
+    "blocked",
+    "rate_limited",
+    "not_found",
+    "server_error",
+    "unsupported_content",
+    "unknown"
+  ],
+  "title": "Status",
+  "type": "string"
+}

changedOutput schema / required

Previous value: -[
-  "markdown",
-  "title",
-  "url",
-  "final_url",
-  "fetched_at",
-  "truncated",
-  "threats",
-  "matches",
-  "provenance"
-]New value: +[
+  "markdown",
+  "title",
+  "url",
+  "final_url",
+  "fetched_at",
+  "status",
+  "http_status",
+  "truncated",
+  "threats",
+  "matches",
+  "provenance"
+]

Changed5 schema fields changedv1.0.0Aug 1, 2026

addedInput schema / properties / format / description

Added value: +"'markdown' extracts the article; 'text' returns the page's rendered text."

addedInput schema / properties / include_hidden / description

Added value: +"Keep text that is invisible to a human reader. It is reported in `threats` either way; this only controls whether it stays in the content."

addedInput schema / properties / max_tokens / description

Added value: +"Token budget for the content. Omit to use the server's GROUNDHOG_MAX_TOKENS (20000 by default). Must be positive."

addedInput schema / properties / query / description

Added value: +"When set, `matches` carries the passages most relevant to it, each with its heading and offset for citation."

addedInput schema / properties / url / description

Added value: +"Absolute http(s) URL. Private and loopback addresses are refused."

First observedAug 1, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Annotations only declare readOnlyHint and openWorldHint, but the description adds real behavioral context: hidden text is stripped by default and surfaced in `threats`, the fetch goes through a stealth browser, and fetches are rate limited per domain (5s apart by default) so multiple pages from one site are slow. That rate-limit disclosure is exactly the kind of side effect an agent must plan around.

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 short sentences, front-loaded with the core action and followed by threat handling, routing, then the rate-limit caveat. Efficient overall, though 'clean, grounded content with provenance' is slightly promotional phrasing that a plainer statement would improve.

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 enumerated, and the description still names the two key output surfaces (`threats`, `matches`). Combined with the rate-limit note, the stealth-fetch behavior, and the sibling routing, an agent has everything needed to call this correctly.

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 description coverage is 100%, so the baseline is 3, but the description goes further by explaining the cross-parameter interplay: hidden text is stripped by default and reported in `threats` regardless, and `matches` carries query-relevant passages. That adds behavioral meaning to `include_hidden` and `query` beyond their individual schema strings.

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 (fetch one web page) plus the mechanism (stealth browser) and the output character (clean, grounded content with provenance). It explicitly distinguishes itself from the siblings `search` and `research`, so an agent can route 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 (ground answers in live web content, including sites that block plain fetchers) and explicit alternatives with the selecting condition: `search` to find URLs, `research` to search and read in one call. The rate-limit note further frames expectations before calling.

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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