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docs(rulebook): C# MCP rules MCP-017/018 + regenerate indexes #12

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docs(rulebook): add Go MCP rules MCP-015/016 + regenerate policy indexes
jhumel-code Jun 6, 2026
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docs(rulebook): add C# MCP rules MCP-017/018 + regenerate indexes
jhumel-code Jun 6, 2026
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150 changes: 77 additions & 73 deletions POLICY_INDEX.md
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6 changes: 3 additions & 3 deletions autogen/POLICY_INDEX.md
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Expand Up @@ -9,13 +9,13 @@ Risk score = `severity_weight × confidence × 100` (engine formula; weights: lo
| -- | ------- | ------- | ----- | --------------------------------------------------- | ------------------------------------------------------------------------ | -------- | ---------- | ---- | --------------------------------------------------------------------------------------------------------- |
| 1 | AG2-001 | AutoGen | agent | autogen_conversable_agent, autogen_user_proxy_agent | AutoGen executor runs code on the host without Docker | high | 0.90 | 63.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/agent_safety.yaml) |
| 2 | AG2-002 | AutoGen | agent | autogen_conversable_agent, autogen_user_proxy_agent | AutoGen executor runs code with no human review (human_input_mode=NEVER) | high | 0.85 | 59.5 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/agent_safety.yaml) |
| 3 | AG2-004 | AutoGen | agent | autogen_group_chat_manager | AutoGen GroupChatManager has no max_round bound | medium | 0.80 | 32.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/agent_safety.yaml) |
| 3 | AG2-004 | AutoGen | agent | autogen_group_chat_manager | AutoGen GroupChatManager has no explicit max_round bound | low | 0.60 | 9.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/agent_safety.yaml) |
| 4 | AG2-005 | AutoGen | agent | autogen_assistant_agent | AutoGen AssistantAgent enables code execution on the LLM agent | medium | 0.70 | 28.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/agent_safety.yaml) |
| 5 | AG2-006 | AutoGen | agent | autogen_conversable_agent, autogen_user_proxy_agent | AutoGen executor with code execution has no auto-reply cap | medium | 0.70 | 28.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/agent_safety.yaml) |
| 5 | AG2-006 | AutoGen | agent | autogen_conversable_agent, autogen_user_proxy_agent | AutoGen executor with code execution has no explicit auto-reply cap | medium | 0.70 | 28.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/agent_safety.yaml) |
| 6 | AG2-007 | AutoGen | tool | autogen_tool | AutoGen tool has no description | low | 0.90 | 13.5 | [tool_definition.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/tool_definition.yaml) |
| 7 | AG2-008 | AutoGen | tool | autogen_tool | AutoGen tool parameters are not type-annotated | medium | 0.85 | 34.0 | [tool_definition.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/tool_definition.yaml) |
| 8 | AG2-009 | AutoGen | tool | autogen_tool | AutoGen tool body spawns a subprocess | high | 0.85 | 59.5 | [shell_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/shell_safety.yaml) |
| 9 | AG2-010 | AutoGen | tool | autogen_tool | AutoGen tool body evaluates dynamic code | high | 0.85 | 59.5 | [code_execution.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/code_execution.yaml) |
| 10 | AG2-011 | AutoGen | tool | autogen_tool | AutoGen tool fetches a caller-controlled URL (SSRF) | high | 0.80 | 56.0 | [ssrf.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/ssrf.yaml) |
| 11 | AG2-012 | AutoGen | tool | autogen_tool | AutoGen tool network call has no timeout | medium | 0.80 | 32.0 | [network.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/network.yaml) |
| 11 | AG2-012 | AutoGen | tool | autogen_tool | AutoGen tool network call has no timeout | high | 0.85 | 59.5 | [network.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/network.yaml) |
| 12 | AG2-201 | AutoGen | repo | autogen | AutoGen project ships no agent-guidance doc (AGENTS.md/CLAUDE.md) | low | 0.90 | 13.5 | [repo_hygiene.yaml](https://github.com/trustabl/trustabl-rules/blob/main/autogen/repo_hygiene.yaml) |
6 changes: 3 additions & 3 deletions claude_sdk/POLICY_INDEX.md
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Expand Up @@ -11,19 +11,19 @@ Risk score = `severity_weight × confidence × 100` (engine formula; weights: lo
| 2 | CSDK-002 | Claude SDK | tool | claude_sdk_tool | Tool parameters are not type-annotated | medium | 0.90 | 36.0 | [tool_definition.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/tool_definition.yaml) |
| 3 | CSDK-003 | Claude SDK | tool | claude_sdk_tool | Network call has no timeout | high | 0.85 | 59.5 | [network.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/network.yaml) |
| 4 | CSDK-004 | Claude SDK | tool | claude_sdk_tool | Path parameter used in I/O without validation | high | 0.70 | 49.0 | [path_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/path_safety.yaml) |
| 5 | CSDK-005 | Claude SDK | tool | claude_sdk_tool | Tool raises exceptions without a structured error contract | medium | 0.60 | 24.0 | [error_handling.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/error_handling.yaml) |
| 5 | CSDK-005 | Claude SDK | tool | claude_sdk_tool | Tool raises exceptions without a structured error contract | low | 0.60 | 9.0 | [error_handling.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/error_handling.yaml) |
| 6 | CSDK-006 | Claude SDK | tool | claude_sdk_tool | Mutating tool has no idempotency key | medium | 0.55 | 22.0 | [idempotency.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/idempotency.yaml) |
| 7 | CSDK-007 | Claude SDK | tool | claude_sdk_tool | Ambiguous tool name | low | 0.90 | 13.5 | [tool_definition.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/tool_definition.yaml) |
| 8 | CSDK-008 | Claude SDK | tool | claude_sdk_tool | Tool exposes **kwargs without explicit input_schema | medium | 0.80 | 32.0 | [tool_definition.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/tool_definition.yaml) |
| 9 | CSDK-009 | Claude SDK | tool | claude_sdk_tool | Tool fetches a caller-controlled URL (SSRF) | high | 0.60 | 42.0 | [ssrf.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/ssrf.yaml) |
| 10 | CSDK-010 | Claude SDK | tool | claude_sdk_tool | TypeScript Claude SDK tool shells out to the OS | high | 0.70 | 49.0 | [shell_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/shell_safety.yaml) |
| 11 | CSDK-011 | Claude SDK | tool | claude_sdk_tool | TypeScript Claude SDK tool evaluates dynamic code | high | 0.90 | 63.0 | [code_execution.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/code_execution.yaml) |
| 12 | CSDK-012 | Claude SDK | tool | claude_sdk_tool | TypeScript Claude SDK tool writes to the filesystem | medium | 0.50 | 20.0 | [path_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/path_safety.yaml) |
| 12 | CSDK-012 | Claude SDK | tool | claude_sdk_tool | TypeScript Claude SDK tool writes to the filesystem | low | 0.50 | 7.5 | [path_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/path_safety.yaml) |
| 13 | CSDK-013 | Claude SDK | tool | claude_sdk_tool | TypeScript Claude SDK tool fetches a caller-controlled URL (SSRF) | high | 0.60 | 42.0 | [ssrf.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/ssrf.yaml) |
| 14 | CSDK-014 | Claude SDK | tool | claude_sdk_tool | TypeScript Claude SDK tool has no description | low | 0.90 | 13.5 | [tool_definition.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/tool_definition.yaml) |
| 15 | CSDK-016 | Claude SDK | tool | claude_sdk_tool | TypeScript Claude SDK mutating tool has no idempotency key | medium | 0.50 | 20.0 | [idempotency.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/idempotency.yaml) |
| 16 | CSDK-101 | Claude SDK | agent | claude_agent_definition | Claude subagent is granted the Bash tool | high | 0.80 | 56.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/agent_safety.yaml) |
| 17 | CSDK-102 | Claude SDK | agent | claude_agent_definition | Claude subagent is granted the WebSearch tool | high | 0.80 | 56.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/agent_safety.yaml) |
| 17 | CSDK-102 | Claude SDK | agent | claude_agent_definition | Claude subagent is granted the WebSearch tool | medium | 0.80 | 32.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/agent_safety.yaml) |
| 18 | CSDK-103 | Claude SDK | agent | claude_agent_definition | AgentDefinition sets permissionMode to bypassPermissions | high | 0.90 | 63.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/agent_safety.yaml) |
| 19 | CSDK-104 | Claude SDK | agent | claude_agent_definition | Claude subagent is granted filesystem-write built-ins | high | 0.80 | 56.0 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/agent_safety.yaml) |
| 20 | CSDK-105 | Claude SDK | agent | claude_agent_definition | Claude subagent is granted the WebFetch tool | high | 0.75 | 52.5 | [agent_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/claude_sdk/agent_safety.yaml) |
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82 changes: 78 additions & 4 deletions docs/Policy/mcp/tool_definition.md
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Expand Up @@ -23,14 +23,34 @@ rules:
confidence: 0.85
scope: tool
fix_type: code
- id: MCP-015
severity: low
confidence: 0.85
scope: tool
fix_type: code
- id: MCP-016
severity: low
confidence: 0.85
scope: tool
fix_type: code
- id: MCP-017
severity: low
confidence: 0.85
scope: tool
fix_type: code
- id: MCP-018
severity: low
confidence: 0.85
scope: tool
fix_type: code
references: [LLM06]
---

# Policy Rationale: MCP Tool Definition Hygiene

**Policy ID:** `mcp_tool_definition`
**File:** `mcp/tool_definition.yaml`
**Rules:** MCP-001, MCP-002, MCP-003, MCP-011
**Rules:** MCP-001, MCP-002, MCP-003, MCP-011, MCP-015, MCP-016, MCP-017, MCP-018
**References:** LLM06 (Excessive Agency)

> Shares the structural-hygiene threat model with
Expand All @@ -44,8 +64,12 @@ references: [LLM06]
The structural hygiene of Model Context Protocol tool registrations — the
Python decorator forms (`@server.tool` / `@mcp.tool` / `.register_tool`,
predicate `mcp_tool` kind) and the TypeScript `@modelcontextprotocol/sdk`
`server.registerTool(...)` / `server.tool(...)` forms. MCP-001/002/003 are the
Python rules; MCP-011 is the TypeScript description rule.
`server.registerTool(...)` / `server.tool(...)` forms, the Go SDKs
(mark3labs/mcp-go's `mcp.NewTool(...)` and the official go-sdk's
`mcp.AddTool(server, &mcp.Tool{...}, fn)`), and the official C# SDK's
`[McpServerTool]`-attributed methods. MCP-001/002/003 are the Python rules;
MCP-011 is the TypeScript description rule; MCP-015/016 are the Go rules;
MCP-017 (no description) and MCP-018 (ambiguous name) are the C# rules.

## Why definition hygiene is sharper for MCP than for an in-process SDK

Expand Down Expand Up @@ -107,6 +131,49 @@ the registration config's `description` is the model's routing signal. Confidenc
0.85 (vs MCP-001's 0.9) reflects that the TypeScript capture can miss a
description supplied through an unusual expression shape.

### MCP-015 — Go MCP tool has no description (Severity: low, Confidence: 0.85, Fix type: code)

**What we detect:** a Go MCP tool whose description is empty
(`has_docstring: false`, reading the captured `Description`) — a mark3labs
`mcp.NewTool("name", ...)` with no `mcp.WithDescription(...)` option, or an
official-SDK `mcp.Tool{...}` with no `Description` field.

**Why it is flaggable:** identical mechanism to MCP-001 / MCP-011 on the Go
SDKs — the description is what the server advertises to connecting clients as the
model's routing signal. Confidence 0.85 mirrors the other description rules; the
residual gap is a description supplied through a non-literal expression, captured
as empty.

### MCP-016 — Ambiguous Go MCP tool name (Severity: low, Confidence: 0.85, Fix type: code)

**What we detect:** a Go MCP tool whose name — the first argument to
`mcp.NewTool(...)`, or the `Name` field of an `mcp.Tool` — is in the fixed
ambiguous set (`process`, `handle`, `run`, ...) via `name_in`.

**Why it is flaggable:** identical to MCP-003 — an ambiguous name gives the model
no intent signal and collides across servers in a shared session, and the cost is
paid by every uncontrolled consumer of the published catalog.

### MCP-017 — C# MCP tool has no description (Severity: low, Confidence: 0.85, Fix type: code)

**What we detect:** an `[McpServerTool]`-attributed C# method with no co-located
`[Description("...")]` attribute (`has_docstring: false`, reading the captured
`Description`).

**Why it is flaggable:** identical mechanism to MCP-001 / MCP-011 / MCP-015 on
the official ModelContextProtocol C# SDK — `[Description]` is what the server
advertises to connecting clients as the model's routing signal. Confidence 0.85
mirrors the other description rules.

### MCP-018 — Ambiguous C# MCP tool name (Severity: low, Confidence: 0.85, Fix type: code)

**What we detect:** an `[McpServerTool]` method whose name (the method name — the
SDK default) is in the fixed ambiguous set (`process`, `handle`, `run`, ...) via
`name_in` (case-insensitive, so PascalCase `Process` matches).

**Why it is flaggable:** identical to MCP-003 / MCP-016 — an ambiguous name gives
the model no intent signal and collides across servers in a shared session.

---

## What this policy does not cover
Expand All @@ -116,4 +183,11 @@ and the low-level `Server` + `setRequestHandler` authoring shape (tools there ar
returned from a `ListTools` handler, not named at a registration call site, so no
per-tool definition is extracted). Resource and prompt registrations
(`@mcp.resource` / `@mcp.prompt`, `registerResource` / `registerPrompt`) are not
yet discovered.
yet discovered. For Go, untyped-params has no analog (Go is statically typed, so
there is no MCP-002 equivalent), the official SDK's handler-struct input schema
and metoro-io/mcp-golang's reflection-based `RegisterTool` are not yet extracted,
and body-fact rules (shell / SSRF / timeout) await Go AST predicates. For C#,
untyped-params likewise has no analog (C# is statically typed), the
`[McpServerTool(Name = "...")]` name override is not read, and body-fact rules
plus the Semantic Kernel `[KernelFunction]` / AutoGen `[Function]` shapes await
later work.
2 changes: 1 addition & 1 deletion google_adk/POLICY_INDEX.md
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Expand Up @@ -11,7 +11,7 @@ Risk score = `severity_weight × confidence × 100` (engine formula; weights: lo
| 2 | ADK-002 | Google ADK | tool | adk_function_tool | FunctionTool-wrapped function has no type-annotated parameters | medium | 0.85 | 34.0 | [tool_definition.yaml](https://github.com/trustabl/trustabl-rules/blob/main/google_adk/tool_definition.yaml) |
| 3 | ADK-003 | Google ADK | tool | adk_function_tool | Network call has no timeout | high | 0.85 | 59.5 | [network.yaml](https://github.com/trustabl/trustabl-rules/blob/main/google_adk/network.yaml) |
| 4 | ADK-004 | Google ADK | tool | adk_function_tool | Path parameter used in I/O without normalization | high | 0.70 | 49.0 | [path_safety.yaml](https://github.com/trustabl/trustabl-rules/blob/main/google_adk/path_safety.yaml) |
| 5 | ADK-005 | Google ADK | tool | adk_function_tool | Tool raises exceptions without a structured error contract | medium | 0.60 | 24.0 | [error_handling.yaml](https://github.com/trustabl/trustabl-rules/blob/main/google_adk/error_handling.yaml) |
| 5 | ADK-005 | Google ADK | tool | adk_function_tool | Tool raises exceptions without a structured error contract | low | 0.60 | 9.0 | [error_handling.yaml](https://github.com/trustabl/trustabl-rules/blob/main/google_adk/error_handling.yaml) |
| 6 | ADK-006 | Google ADK | tool | adk_function_tool | Mutating tool has no idempotency key | medium | 0.55 | 22.0 | [idempotency.yaml](https://github.com/trustabl/trustabl-rules/blob/main/google_adk/idempotency.yaml) |
| 7 | ADK-007 | Google ADK | tool | adk_function_tool | Ambiguous tool name | low | 0.90 | 13.5 | [tool_definition.yaml](https://github.com/trustabl/trustabl-rules/blob/main/google_adk/tool_definition.yaml) |
| 8 | ADK-008 | Google ADK | agent | adk_llm_agent | Agent grants BashTool with no restrictive command policy | high | 0.75 | 52.5 | [builtin_tools.yaml](https://github.com/trustabl/trustabl-rules/blob/main/google_adk/builtin_tools.yaml) |
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