## Summary
- rename the multi-agent v2 follow-up task tool surface to assign_task
- update core tests and spec-plan expectations
- keep rollout-trace classification backward-compatible with legacy
followup_task
## Tests
- just fmt
- just test -p codex-core
multi_agents_spec::tests::assign_task_tool_requires_message_and_has_no_output_schema
- just test -p codex-rollout-trace
- just fix -p codex-core
- just fix -p codex-rollout-trace
Note: a broad just test -p codex-core run was attempted locally, but
this sandbox produced unrelated environment failures around
sandbox-exec, missing test_stdio_server, and realtime timeouts.
## Why
The MCP tool path had accumulated a few core-owned special cases: a
dedicated payload variant, resolver plumbing, a legacy `AfterToolUse`
translation path, and a side channel for parallel-call metadata. That
made `ToolRegistry` and the spec builder know more about MCP than they
needed to.
This change moves MCP-specific execution details back onto `ToolInfo`
and `McpHandler` so `codex-core` can treat MCP calls like normal
function calls while still preserving MCP-specific dispatch and
telemetry behavior where it belongs.
## What changed
- removed `resolve_mcp_tool_info`, `ToolPayload::Mcp`, `ToolKind`, and
the remaining registry-side MCP resolver path
- stored MCP routing metadata directly on `McpHandler` and `ToolInfo`,
including `supports_parallel_tool_calls`
- deleted the legacy `AfterToolUse` consumer in `core`, which removes
the need for handler-specific `after_tool_use_payload` implementations
- switched tool-result telemetry to handler-provided tags and kept
MCP-specific dispatch payload construction inside the handler
- simplified tool spec planning/building by passing `ToolInfo` directly
and dropping the direct/deferred MCP wrapper structs and the
parallel-server side table
## Testing
- `cargo check -p codex-core -p codex-mcp -p codex-otel`
- `cargo test -p codex-core
mcp_parallel_support_uses_exact_payload_server`
- `cargo test -p codex-core
direct_mcp_tools_register_namespaced_handlers`
- `cargo test -p codex-core
search_tool_description_lists_each_mcp_source_once`
- `cargo test -p codex-mcp
list_all_tools_uses_startup_snapshot_while_client_is_pending`
- `just fix -p codex-core -p codex-mcp -p codex-otel`
## Why
`PermissionProfile` is becoming the canonical permissions abstraction,
but the old shape only carried optional filesystem and network fields.
It could describe allowed access, but not who is responsible for
enforcing it. That made `DangerFullAccess` and `ExternalSandbox` lossy
when profiles were exported, cached, or round-tripped through app-server
APIs.
The important model change is that active permissions are now a disjoint
union over the enforcement mode. Conceptually:
```rust
pub enum PermissionProfile {
Managed {
file_system: FileSystemSandboxPolicy,
network: NetworkSandboxPolicy,
},
Disabled,
External {
network: NetworkSandboxPolicy,
},
}
```
This distinction matters because `Disabled` means Codex should apply no
outer sandbox at all, while `External` means filesystem isolation is
owned by an outside caller. Those are not equivalent to a broad managed
sandbox. For example, macOS cannot nest Seatbelt inside Seatbelt, so an
inner sandbox may require the outer Codex layer to use no sandbox rather
than a permissive one.
## How Existing Modeling Maps
Legacy `SandboxPolicy` remains a boundary projection, but it now maps
into the higher-fidelity profile model:
- `ReadOnly` and `WorkspaceWrite` map to `PermissionProfile::Managed`
with restricted filesystem entries plus the corresponding network
policy.
- `DangerFullAccess` maps to `PermissionProfile::Disabled`, preserving
the “no outer sandbox” intent instead of treating it as a lax managed
sandbox.
- `ExternalSandbox { network_access }` maps to
`PermissionProfile::External { network }`, preserving external
filesystem enforcement while still carrying the active network policy.
- Split runtime policies that legacy `SandboxPolicy` cannot faithfully
express, such as managed unrestricted filesystem plus restricted
network, stay `Managed` instead of being collapsed into
`ExternalSandbox`.
- Per-command/session/turn grants remain partial overlays via
`AdditionalPermissionProfile`; full `PermissionProfile` is reserved for
complete active runtime permissions.
## What Changed
- Change active `PermissionProfile` into a tagged union: `managed`,
`disabled`, and `external`.
- Keep partial permission grants separate with
`AdditionalPermissionProfile` for command/session/turn overlays.
- Represent managed filesystem permissions as either `restricted`
entries or `unrestricted`; `glob_scan_max_depth` is non-zero when
present.
- Preserve old rollout compatibility by accepting the pre-tagged `{
network, file_system }` profile shape during deserialization.
- Preserve fidelity for important edge cases: `DangerFullAccess`
round-trips as `disabled`, `ExternalSandbox` round-trips as `external`,
and managed unrestricted filesystem + restricted network stays managed
instead of being mistaken for external enforcement.
- Preserve configured deny-read entries and bounded glob scan depth when
full profiles are projected back into runtime policies, including
unrestricted replacements that now become `:root = write` plus deny
entries.
- Regenerate the experimental app-server v2 JSON/TypeScript schema and
update the `command/exec` README example for the tagged
`permissionProfile` shape.
## Compatibility
Legacy `SandboxPolicy` remains available at config/API boundaries as the
compatibility projection. Existing rollout lines with the old
`PermissionProfile` shape continue to load. The app-server
`permissionProfile` field is experimental, so its v2 wire shape is
intentionally updated to match the higher-fidelity model.
## Verification
- `just write-app-server-schema`
- `cargo check --tests`
- `cargo test -p codex-protocol permission_profile`
- `cargo test -p codex-protocol
preserving_deny_entries_keeps_unrestricted_policy_enforceable`
- `cargo test -p codex-app-server-protocol
permission_profile_file_system_permissions`
- `cargo test -p codex-app-server-protocol serialize_client_response`
- `cargo test -p codex-core
session_configured_reports_permission_profile_for_external_sandbox`
- `just fix`
- `just fix -p codex-protocol`
- `just fix -p codex-app-server-protocol`
- `just fix -p codex-core`
- `just fix -p codex-app-server`
## Summary
Extends rollout tracing across tool dispatch and code-mode runtime
boundaries. This records canonical tool-call lifecycle events and links
code-mode execution/wait operations back to the model-visible calls that
caused them.
## Stack
This is PR 3/5 in the rollout trace stack.
- [#18876](https://github.com/openai/codex/pull/18876): Add rollout
trace crate
- [#18877](https://github.com/openai/codex/pull/18877): Record core
session rollout traces
- [#18878](https://github.com/openai/codex/pull/18878): Trace tool and
code-mode boundaries
- [#18879](https://github.com/openai/codex/pull/18879): Trace sessions
and multi-agent edges
- [#18880](https://github.com/openai/codex/pull/18880): Add debug trace
reduction command
## Review Notes
This PR is about attribution. Reviewers should focus on whether direct
tool calls, code-mode-originated tool calls, waits, outputs, and
cancellation boundaries are recorded with enough source information for
deterministic reduction without coupling the reducer to live runtime
internals.
The stack remains valid after this layer: tool and code-mode traces
reduce through the existing crate model, while the broader session and
multi-agent relationships are added in the next PR.