## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work.
> - ACP agents can request permission before reads, process execution,
and workspace mutation.
> - The runner must apply the configured policy without allowing
provider display text to grant authority.
> - Runner-owned semantic tools already have a separate run-scoped
authorization catalog.
> - This pull request defines the local permission decision and the
narrow metadata needed to recognize those authorized tools.
> - The benefit is a fail-closed permission boundary before an ACPX
process can use it.
## Linked Issues or Issue Description
**Agent or provider**
Qualified Pi, Claude, and Codex ACP servers through the internal ACPX
driver.
**Why this adapter is useful**
ACP providers use permission requests for both ordinary provider
operations and runner-owned semantic operations. Paperclip must apply
`approve-all`, `approve-reads`, or `deny-all` consistently while keeping
semantic authorization bound to structural MCP metadata.
**How the agent is invoked**
A later pull request will install this policy in the private ACPX
runtime host. This pull request does not launch a provider, add a
dependency, register an adapter, or change runtime selection.
**Additional context**
This pull request is stacked on #12390. Pi uses a different bridge and
never receives semantic auto-approval through this ACP permission path.
## What Changed
- Map each ACPX permission mode to a closed runtime policy.
- Decide local allow, reject, or coordinator delegation outcomes.
- Auto-approve only runner-owned semantic MCP calls identified by
structural metadata.
- Ignore provider display titles when determining semantic authority.
- Limit Codex blanket MCP approval to sessions where every configured
MCP server is runner-owned.
- Add table-driven tests for all modes, agents, metadata shapes, spoofed
titles, and non-runner servers.
## Verification
- Runner TypeScript typecheck — passed.
- Runner TypeScript tests — passed, including 10 new permission-policy
assertions.
- `pnpm -r typecheck` — passed for all applicable workspaces.
- `pnpm build` — passed, including runner binary, server, UI, and
workspace packages.
- Prettier and `git diff --check` — passed.
- The diff contains 2 files and does not change `pnpm-lock.yaml`, a
workflow, a dependency, a public export, server selection, or UI
behavior.
## Risks
The main risk is mistaking a provider-controlled label for an authorized
semantic tool. The implementation ignores display titles and requires a
runner-owned MCP server name, a transport tool name, or provider
metadata. All other `approve-reads` mutations delegate to the
coordinator, and the caller must reject them when no delegate exists.
## Model Used
OpenAI Codex with GPT-5 and repository tool use.
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either linked an existing public item or described the
issue in this PR
- [x] I have not referenced internal or instance-local Paperclip issues
or links
- [x] My branch name describes the change and contains no internal task
identifier
- [x] I have run the affected tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have documented the permission and semantic-authorization
boundary
- [ ] All applicable GitHub Actions are green
- [ ] Greptile is 5/5 with every actionable comment resolved
- [x] I will address all review findings before requesting merge
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