Python: Add name collision warnings for auto-approvals

[westey-m]

Motivation & Context

Defense in depth

Description & Review Guide

Fully document how auto-approval rules match by name only, and warn users to ensure that there are no name collisions.

Related Issue

#7088

Contribution Checklist

• The code builds clean without any errors or warnings
• All unit tests pass, and I have added new tests where possible
• The PR follows the Contribution Guidelines
• This PR is linked to an issue and there is no other open PR for this issue (see Related Issue above).
• This is not a breaking change. If it is a breaking change, add the breaking change label (or add "[BREAKING]" to the title prefix, before or after any language prefix) — a workflow keeps the label and title prefix in sync automatically.

[Copilot]

Pull request overview

This PR adds explicit security documentation warning that built-in tool auto-approval rules can match by tool name and may unintentionally auto-approve unrelated tools if names collide, encouraging users to avoid reserved tool-name collisions as a defense-in-depth measure.

Changes:

• Added name-collision security warnings to the skills auto-approval and harness sample READMEs.
• Added .. warning:: documentation to built-in auto-approval rule docstrings (SkillsProvider/FileAccessProvider) and to ToolApprovalMiddleware guidance.
• Documented the same collision risk on the configurable shell tool as_function(name=...) API in both local and Docker implementations.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
python/samples/02-agents/skills/skills_auto_approval/README.md	Adds a security callout warning about reserved tool-name collisions for skills auto-approval rules.
python/samples/02-agents/harness/README.md	Documents collision risk for built-in auto-approval rules in the harness security considerations section.
python/samples/02-agents/harness/build_your_own_claw/README.md	Adds an in-sample warning about auto-approval matching by tool name for file-access tools.
python/packages/tools/agent_framework_tools/shell/_tool.py	Adds docstring warning that caller-chosen shell tool names can collide with auto-approval rules.
python/packages/tools/agent_framework_tools/shell/_docker.py	Adds the same docstring warning for DockerShellTool’s as_function naming.
python/packages/core/agent_framework/_skills.py	Adds .. warning:: blocks documenting collision risk for SkillsProvider auto-approval rules.
python/packages/core/agent_framework/_harness/_tool_approval.py	Adds warning guidance in ToolApprovalMiddleware docs about name-based auto-approval collisions.
python/packages/core/agent_framework/_harness/_file_access.py	Adds .. warning:: blocks documenting collision risk for FileAccessProvider auto-approval rules.

[github-actions]

Flagged issue

Docs-only here leaves the approval bypass fully intact: ToolApprovalMiddleware auto-approves any request for which a callback returns true (_tool_approval.py:620-629), the built-in file-access and skills rules still match only on function_call.name (_file_access.py:1379-1382, _skills.py:198-1991), and LocalShellTool.as_function still lets calers choose any exposed name (shell/_tool.py:278-319). That means LocalShellTool().as_function(name="file_access_read") will still be auto-approved without a prompt when FileAccessProvider.read_only_tools_auto_approval_rule is installed. The repo already uses a stronger pattern for reserved names in progressive MCP mode by actively rejecting/omitting colliding tools instead of warning about them (_mcp.py:885-895, _mcp.py:1030-1035).

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Source: automated DevFlow PR review

[github-actions]

Automated Code Review

Reviewers: 5 | Confidence: 85%

✓ Correctness

This PR is purely documentation: it adds security warnings about tool-name collision risks in auto-approval rules across docstrings, README files, and the shell tool's as_function method. All documented tool names were verified against the actual code constants and match exactly. The warnings accurately describe the name-based matching behavior of the approval rules. No correctness issues found.

✓ Security Reliability

This PR adds documentation-only security warnings about tool-name collision risks in auto-approval rules. The warnings are accurate: the existing rules approve local tool calls by name (plus a server_label check to exclude hosted tools), so a local tool registered under a colliding name could be auto-approved. No code logic is changed, and no security or reliability issues are introduced by these documentation additions.

✓ Test Coverage

This PR adds documentation-only changes (docstring warnings and README updates) about tool-name collision risks in auto-approval rules. No behavioral code is changed. Existing tests cover the auto-approval rules' intended behavior well, including rejection of hosted tools with matching names. However, the specific collision scenario being warned about — a local tool (e.g., shell tool) given a custom name matching an auto-approved tool name — is not tested anywhere. Since the PR is purely documentation, no blocking issues are raised, but a demonstrative test would strengthen the defense-in-depth intent.

✓ Failure Modes

This PR is entirely documentation: it adds security warnings to docstrings and README files about tool-name collision risks with auto-approval rules. No functional code is changed — only .. warning:: blocks in Python docstrings and markdown callouts in sample READMEs. There are no failure modes introduced by these changes.

✗ Design Approach

The PR improves documentation, but it leaves the underlying approval-boundary collision unmitigated. The current design still silently auto-approves any local tool whose name matches a built-in auto-approval rule, including caller-renamed shell tools, so documenting the hazard alone does not address the security failure mode this PR describes.

Flagged Issues

• Docs-only here leaves the approval bypass fully intact: ToolApprovalMiddleware auto-approves any request for which a callback returns true (_tool_approval.py:620-629), the built-in file-access and skills rules still match only on function_call.name (_file_access.py:1379-1382, _skills.py:198-1991), and LocalShellTool.as_function still lets calers choose any exposed name (shell/_tool.py:278-319). That means LocalShellTool().as_function(name="file_access_read") will still be auto-approved without a prompt when FileAccessProvider.read_only_tools_auto_approval_rule is installed. The repo already uses a stronger pattern for reserved names in progressive MCP mode by actively rejecting/omitting colliding tools instead of warning about them (_mcp.py:885-895, _mcp.py:1030-1035).

Suggestions

• Enforce reserved auto-approved names at runtime rather than only documenting them — for example, reject tool registration or middleware setup when a local tool requiring approval is exposed under a name claimed by one of the built-in auto-approval rules, mirroring the collision handling used for progressive MCP loader names (_mcp.py:885-895, _mcp.py:1030-1035).

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Automated review by westey-m's agents

[github-actions]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
packages/core/agent_framework
_skills.py	1083	39	96%	314, 584, 1102, 1117, 1119–1120, 1486–1487, 1729, 1758, 2270, 2459, 2967–2968, 3065, 3073, 3078, 3081, 3086, 3106, 3118, 3123, 3218, 3226, 3231, 3234, 3239, 3259, 3268, 3273, 3539–3540, 4092, 4340–4341, 4368–4369, 4376–4377
packages/core/agent_framework/_harness
_file_access.py	614	45	92%	187, 218, 281, 391, 393, 405, 409, 437, 450–451, 458–465, 469, 473, 839–840, 866, 870, 924–926, 948–951, 1445–1446, 1457–1458, 1470–1471, 1485–1486, 1509–1510, 1525, 1530–1531, 1560
_tool_approval.py	358	44	87%	69, 72, 77, 115, 132, 135, 138, 196–197, 216, 245, 253, 264, 282–287, 299, 313, 316, 336, 387, 410, 412–413, 445, 455, 470, 472–473, 475–476, 501–502, 523–525, 563–564, 614, 618, 623
packages/tools/agent_framework_tools/shell
_docker.py	232	124	46%	135, 143–144, 381–383, 391–400, 406, 412, 416–421, 423–426, 429–430, 433, 448–456, 458, 460–465, 467, 473–474, 498–506, 508–509, 514–518, 524, 533–542, 547, 555–558, 564–568, 572–574, 579, 584, 586–589, 601, 616, 621–623, 626, 635, 637, 645–652, 654–657, 663–664, 667, 702–706
_tool.py	104	15	85%	156, 158, 179–180, 182, 201, 254–255, 263, 306–310, 331
TOTAL	44212	5244	88%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
8890	33 💤	0 ❌	0 🔥	1m 57s ⏱️