Zambo

PDF Extract

pdf_extract

Read-onlyIdempotent

Fetch and extract text content from any public URL - PDF documents, web pages, articles, docs. Returns the extracted text, word count, and a summary. Works on research papers, contracts, articles, reports. Use when user says 'read this PDF', 'extract from this URL', 'summarize this document', 'what does this say'. AER-1 receipt, verifiable offline. Required arguments: url.

Input Schema

Name	Required	Description	Default
`url`	Yes	Public URL to the document or webpage to extract and summarize.
`_ref`	No	Optional handover referral ID from your install link.
`max_chars`	No	Max characters of raw text to return (default: 4000, max: 8000).
`summarize`	No	Also generate an AI summary. Default: true.
`_zambo_key`	No	Optional opaque Zambo access capability. Never place it in a URL or public log.
`_session_id`	No	Optional stable bot-job ID. Reuse it across calls to bind a Day Pass and keep the job ledger together.
`_caller_label`	No	Optional caller label recorded as a caller-reported claim in the receipt.	zambo-starter
`_caller_handle`	No	Opaque anonymous continuity handle returned during initialize. Reuse it across MCP sessions; it is not payment authorization.
`_continuity_ai_label`	No	Optional self-reported AI client label for the private continuity timeline. Zambo does not independently verify the client.

Output Schema

Name	Required	Description
`ok`	Yes
`ids`	Yes
`next`	Yes
`tier`	No
`urls`	Yes
`error`	No
`graph`	No
`active`	No
`result`	Yes	The tool's observed JSON value or plain-text result.
`intents`	No
`next_up`	No
`payment`	No
`day_pass`	No
`today_url`	No
`expires_at`	No
`human_line`	Yes
`next_steps`	No
`daily_recap`	No
`renew_nudge`	No
`unlock_link`	No
`seconds_left`	No
`resume_status`	No
`resumed_result`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedOct 25, 2026

addedInput schema / properties / _caller_handle

Added value: +{
+  "description": "Opaque anonymous continuity handle returned during initialize. Reuse it across MCP sessions; it is not payment authorization.",
+  "maxLength": 64,
+  "type": "string"
+}

addedInput schema / properties / _caller_label / default
```
Added value: +"zambo-starter"
```

Changed1 schema field changedOct 23, 2026
- changedOutput schema / properties / graph / properties / aer / const
```
Previous value: -"draft-zambo-aer1-25"New value: +"draft-zambo-aer1-26"
```
Changed1 schema field changedOct 22, 2026
- changedOutput schema / properties / graph / properties / aer / const
```
Previous value: -"draft-zambo-aer1-24"New value: +"draft-zambo-aer1-25"
```
Changed1 schema field changedOct 20, 2026
- changedOutput schema / properties / graph / properties / aer / const
```
Previous value: -"draft-zambo-aer1-23"New value: +"draft-zambo-aer1-24"
```
Changed1 schema field changedOct 19, 2026
- changedOutput schema / properties / graph / properties / aer / const
```
Previous value: -"draft-zambo-aer1-22"New value: +"draft-zambo-aer1-23"
```
Changed1 schema field changedOct 18, 2026
- changedOutput schema / properties / graph / properties / aer / const
```
Previous value: -"draft-zambo-aer1-21"New value: +"draft-zambo-aer1-22"
```
Changed1 schema field changedOct 18, 2026
- changedOutput schema / properties / graph / properties / aer / const
```
Previous value: -"draft-zambo-aer1-20"New value: +"draft-zambo-aer1-21"
```
Changed1 schema field changedOct 17, 2026
- addedOutput schema / properties / next_steps
```
Added value: +{
+  "items": {},
+  "minItems": 1,
+  "type": "array"
+}
```

Changed12 schema fields changedOct 17, 2026

addedInput schema / properties / _ref

Added value: +{
+  "description": "Optional handover referral ID from your install link.",
+  "format": "uuid",
+  "type": "string"
+}

changedOutput schema / additionalProperties
```
Previous value: -falseNew value: +true
```

addedOutput schema / properties / error

Added value: +{
+  "additionalProperties": true,
+  "anyOf": [
+    {
+      "required": [
+        "next_call"
+      ]
+    },
+    {
+      "required": [
+        "next_url"
+      ]
+    }
+  ],
+  "properties": {
+    "code": {
+      "type": "string"
+    },
+    "next_call": {
+      "additionalProperties": false,
+      "properties": {
+        "args": {
+          "type": "object"
+        },
+        "tool": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "tool",
+        "args"
+      ],
+      "type": "object"
+    },
+    "next_step": {
+      "type": "string"
+    },
+    "next_url": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "code",
+    "next_step"
+  ],
+  "type": "object"
+}

addedOutput schema / properties / graph

Added value: +{
+  "properties": {
+    "aer": {
+      "const": "draft-zambo-aer1-20"
+    },
+    "schema": {
+      "const": "zambo.graph/1"
+    }
+  },
+  "required": [
+    "schema",
+    "aer",
+    "nodes",
+    "edges",
+    "retries",
+    "sources",
+    "summary"
+  ],
+  "type": "object"
+}

addedOutput schema / properties / human_line / maxLength
```
Added value: +200
```
addedOutput schema / properties / human_line / pattern
```
Added value: +"^[^\\r\\n]*$"
```

addedOutput schema / properties / ids

Added value: +{
+  "additionalProperties": {
+    "type": "string"
+  },
+  "type": "object"
+}

addedOutput schema / properties / next

Added value: +{
+  "minLength": 1,
+  "type": "string"
+}

addedOutput schema / properties / ok
```
Added value: +{
+  "type": "boolean"
+}
```
addedOutput schema / properties / renew_nudge
```
Added value: +{
+  "type": "object"
+}
```

addedOutput schema / properties / urls

Added value: +{
+  "additionalProperties": {
+    "type": "string"
+  },
+  "type": "object"
+}

changedOutput schema / required

Previous value: -[
-  "result"
-]New value: +[
+  "result",
+  "ok",
+  "human_line",
+  "next",
+  "ids",
+  "urls"
+]

Changed14 schema fields changedOct 16, 2026

addedOutput schema / properties / active
```
Added value: +{
+  "type": "boolean"
+}
```
addedOutput schema / properties / daily_recap
```
Added value: +{
+  "type": "object"
+}
```
addedOutput schema / properties / day_pass
```
Added value: +{
+  "type": "object"
+}
```

addedOutput schema / properties / expires_at

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

addedOutput schema / properties / human_line
```
Added value: +{
+  "type": "string"
+}
```

addedOutput schema / properties / intents

Added value: +{
+  "items": {
+    "type": "object"
+  },
+  "type": "array"
+}

addedOutput schema / properties / next_up
```
Added value: +{
+  "type": "string"
+}
```
addedOutput schema / properties / payment
```
Added value: +{
+  "type": "object"
+}
```
addedOutput schema / properties / resume_status
```
Added value: +{
+  "type": "string"
+}
```
addedOutput schema / properties / resumed_result
```
Added value: +{
+  "type": "object"
+}
```

addedOutput schema / properties / seconds_left

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

addedOutput schema / properties / tier

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

addedOutput schema / properties / today_url
```
Added value: +{
+  "type": "string"
+}
```

addedOutput schema / properties / unlock_link

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

Changed3 schema fields changedOct 10, 2026

changedInput schema / properties / _caller_label / description

Previous value: -"Optional self-reported caller label. It is recorded as a claim, not independently verified."New value: +"Optional caller label recorded as a caller-reported claim in the receipt."

changedInput schema / properties / _session_id / description

Previous value: -"Optional stable Zambo session ID used to preserve continuity across tool calls."New value: +"Optional stable bot-job ID. Reuse it across calls to bind a Day Pass and keep the job ledger together."

addedInput schema / properties / _zambo_key

Added value: +{
+  "description": "Optional opaque Zambo access capability. Never place it in a URL or public log.",
+  "maxLength": 160,
+  "type": "string"
+}

Changed4 schema fields changedOct 10, 2026
- changedOutput schema / additionalProperties
```
Previous value: -trueNew value: +false
```
- addedOutput schema / properties / result / description
```
Added value: +"The tool's observed JSON value or plain-text result."
```
- removedOutput schema / properties / result / type
```
Removed value: -"string"
```
- addedOutput schema / required
```
Added value: +[
+  "result"
+]
```

Changed2 schema fields changedOct 10, 2026

addedInput schema / properties / _caller_label

Added value: +{
+  "description": "Optional self-reported caller label. It is recorded as a claim, not independently verified.",
+  "maxLength": 80,
+  "type": "string"
+}

addedInput schema / properties / _session_id

Added value: +{
+  "description": "Optional stable Zambo session ID used to preserve continuity across tool calls.",
+  "maxLength": 64,
+  "type": "string"
+}

AddedOct 2, 2026

TDQS

A4/5.0

Behavior3/5

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description usefully discloses the return payload and an "AER-1 receipt, verifiable offline", but leaves unexplained what happens on non-public URLs, fetch failures, or large-document truncation, and "AER-1" is unexplained jargon.

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 the core action and the trigger phrases are compact and high-value. Minor waste from overlapping enumerations ("PDF documents, web pages, articles, docs" followed by "research papers, contracts, articles, reports"), but nothing is confusingly 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?

Output schema exists, so return values need no further explanation; parameters are fully documented in-schema; annotations carry safety semantics. For a read-only fetch/extract tool this is sufficient to call correctly, with only error-path behavior left implicit.

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 description coverage is 100%, so all nine parameters are already documented in-schema. The description only repeats "Required arguments: url." without adding formatting, constraints, or guidance on max_chars/summarize tradeoffs, so it earns the baseline rather than more.

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 and extract text content") and explicitly broadens scope beyond the name: PDFs, web pages, articles, docs. It also names the return payload (text, word count, summary), so an agent knows exactly what it gets 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?

Provides concrete user-utterance triggers ("read this PDF", "extract from this URL", "summarize this document"), which is strong routing guidance. It does not state exclusions or when-not-to-use cases (e.g. private/paywalled URLs), but no sibling tool overlaps this purpose, so the omission is low-risk.

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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