[tool search] support namespaced deferred dynamic tools by pash-openai · Pull Request #18413 · openai/codex

pash-openai · 2026-04-17T23:26:38Z

Deferred dynamic tools need to round-trip a namespace so a tool returned by tool_search can be called through the same registry key that core uses for dispatch.

This change adds namespace support for dynamic tool specs/calls, persists it through app-server thread state, and routes dynamic tool calls by full ToolName while still sending the app the leaf tool name. Deferred dynamic tools must provide a namespace; non-deferred dynamic tools may remain top-level.

It also introduces LoadableToolSpec as the shared function-or-namespace Responses shape used by both tool_search output and dynamic tool registration, so dynamic tools use the same wrapping logic in both paths.

Validation:

cargo test -p codex-tools
cargo test -p codex-core tool_search

pash-openai · 2026-04-17T23:50:27Z

@codex review

chatgpt-codex-connector · 2026-04-17T23:53:42Z

Codex Review: Didn't find any major issues. 🎉

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pash-openai · 2026-04-18T01:42:20Z

@codex review

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codex/codex-rs/app-server/src/codex_message_processor.rs

Lines 9206 to 9208 in ad75171

    
           if name == "mcp" || name.starts_with("mcp__") { 
        
               return Err(format!("dynamic tool name is reserved: {name}")); 
        
           }

Validate dynamic tool namespaces against reserved prefixes

validate_dynamic_tools only checks tool.name for reserved mcp prefixes and duplicate conflicts, but never validates tool.namespace. A dynamic tool can therefore use an MCP namespace/name pair and collide with real MCP tools. That key is later registered as a dynamic handler and can overwrite the existing handler, causing tool calls to be routed to the wrong backend.

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pakrym-oai · 2026-04-18T01:53:31Z

what is this used for that we don't care about ns?

when making the actual leaf ResponsesApiTool function, we dont care about the namespace, because these leaf functions are contained in a ResponsesApiNamespace where the namespace is captured.

mcp tools do the same thing here (ignoring namespace when making ResponsesApiTool).

pash-openai · 2026-04-18T20:25:35Z

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pash-openai · 2026-04-18T20:43:43Z

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pash-openai · 2026-04-19T00:16:01Z

@codex review

chatgpt-codex-connector · 2026-04-19T00:21:57Z

Review result: changes requested

I re-reviewed the PR state at b619c18 and found one remaining contract bug.

1) P2 — `namespace` is optional in Rust/JSON Schema but required in generated TS

DynamicToolSpec.namespace is declared as Option<String> in Rust, but it is missing #[ts(optional = nullable)], so the generated TypeScript type requires the field (namespace: string | null) instead of making it optional. That can break existing TS callers that omit namespace. codex-rs/app-server-protocol/src/protocol/v2.rsL607-L617 codex-rs/app-server-protocol/schema/typescript/v2/DynamicToolSpec.tsL1-L6
JSON Schema still treats namespace as optional (required excludes it), confirming the mismatch is real at the API contract boundary. codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.jsonL3867-L3891

Notes on previously flagged items

The reserved-namespace validation issue appears addressed: validate_dynamic_tools now rejects reserved prefixes for both name and namespace (including mcp__...). codex-rs/app-server/src/codex_message_processor.rsL9193-L9228
Deferred namespaced dynamic tools appear aligned in registry planning (namespace spec + namespaced handler), with test coverage asserting the namespaced handler key for deferred tools. codex-rs/tools/src/tool_registry_plan.rsL559-L578 codex-rs/tools/src/tool_registry_plan_tests.rsL1411-L1462

Checks run

✅ git show --stat --oneline b619c1801f961033fbfb3dfb266cde4a3fbce0d0
✅ nl -ba codex-rs/app-server-protocol/src/protocol/v2.rs | sed -n '600,640p'
✅ nl -ba codex-rs/app-server-protocol/schema/typescript/v2/DynamicToolSpec.ts
✅ nl -ba codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json | sed -n '3860,3925p'
✅ nl -ba codex-rs/app-server/src/codex_message_processor.rs | sed -n '9190,9245p'
✅ nl -ba codex-rs/tools/src/tool_registry_plan.rs | sed -n '552,590p'
✅ nl -ba codex-rs/tools/src/tool_registry_plan_tests.rs | sed -n '1411,1465p'

No code changes were made in this pass, so no commit/PR was created.

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pash-openai · 2026-04-19T05:09:12Z

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chatgpt-codex-connector · 2026-04-19T05:16:35Z

+    {
+        tool_name.display()
+    } else {
+        tool_name.name.clone()


Preserve namespaces in code-mode tool names

Return a fully-qualified name for non-MCP namespaced tools. Flattening to tool_name.name makes different tools share the same code-mode identifier (e.g. shell), and later dedup/lookup logic is name-based. This can hide one tool from ALL_TOOLS and route tools.<name>(...) to the wrong handler when names collide across namespaces or with built-ins.

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sayan-oai · 2026-04-20T22:49:53Z


 fn dynamic_tool_search_entry(tool: &DynamicToolSpec) -> Result<ToolSearchEntry, serde_json::Error> {
+    let output_tool = dynamic_tool_to_responses_api_tool(tool)?;
+    let output = match tool.namespace.as_ref() {


because dynamic tools can now be namespaced

sayan-oai · 2026-04-20T22:50:58Z

+        Some(namespace) => format!("{namespace}_{}", tool_name.name),
+        None => tool_name.name.clone(),
+    }


localized to code_mode; this makes it so the functions created from namespaced tools look reasonable (codex_apps_foo_tool rather than codex_appsfoo_tool)

pakrym-oai · 2026-04-20T23:55:23Z

 }

 fn dynamic_tool_search_entry(tool: &DynamicToolSpec) -> Result<ToolSearchEntry, serde_json::Error> {
+    let output_tool = dynamic_tool_to_responses_api_tool(tool)?;


really dislike how many layers of transformations we go through to build a tool definition.

reworked to go direct from DynamicToolSpec -> ResponsesApiTool.

renamed ToolSearchOutputTool to LoadableToolSpec (lmk if there's a clearer name) as a side effect so we can use this across dynamic tool parsing in tool search and in tool registration.

sayan-oai · 2026-04-21T03:19:33Z

@codex review this

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chatgpt-codex-connector · 2026-04-21T03:37:17Z

+pub fn code_mode_name_for_tool_name(tool_name: &ToolName) -> String {
+    match tool_name.namespace.as_deref() {
+        Some(namespace) if namespace.ends_with('_') || tool_name.name.starts_with('_') => {
+            format!("{namespace}{}", tool_name.name)
+        }
+        Some(namespace) => format!("{namespace}_{}", tool_name.name),
+        None => tool_name.name.clone(),


Make code-mode tool name mapping collision-free

code_mode_name_for_tool_name is not one-to-one. Different (namespace, name) pairs can produce the same code-mode name (e.g. (a, b_c) and (a_b, c) both map to a_b_c). Code mode uses this value as the tools object key, so later tools overwrite earlier ones and one callable becomes unreachable.

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chatgpt-codex-connector · 2026-04-21T03:37:17Z

+            if namespace == "mcp" || namespace.starts_with("mcp__") {
+                return Err(format!(
+                    "dynamic tool namespace is reserved for {name}: {namespace}"
+                ));
+            }
+        }
+        if !seen.insert((namespace, name)) {
+            if let Some(namespace) = namespace {


Reject dynamic tools that shadow existing namespaced tools

Validation only blocks mcp* namespaces and duplicate names within the dynamic list. It allows a dynamic tool to reuse another registered (namespace, name) pair (e.g. connector namespaces), and handler registration then overwrites the existing handler for that key. Calls can be silently routed to the wrong tool.

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chatgpt-codex-connector · 2026-04-21T03:37:17Z

    for tool in params.dynamic_tools {
-        match dynamic_tool_to_responses_api_tool(tool) {
-            Ok(converted_tool) => {
+        match dynamic_tool_to_loadable_tool_spec(tool) {
+            Ok(loadable_tool) => {
+                let handler_name = ToolName::new(tool.namespace.clone(), tool.name.clone());
                plan.push_spec(
-                    ToolSpec::Function(converted_tool),
+                    loadable_tool.into(),
                    /*supports_parallel_tool_calls*/ false,


Coalesce duplicate dynamic namespace specs before registration

build_tool_registry_plan pushes each namespaced dynamic tool as its own ToolSpec::Namespace. Multiple tools in one namespace therefore emit repeated namespace wrappers, unlike MCP where entries are grouped first. This bloats tool payloads and can create ambiguous duplicate namespace declarations in model-visible specs.

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Is this true?

Sounds true

pakrym-oai · 2026-04-21T05:15:46Z

    }
 }

+impl From<LoadableToolSpec> for ToolSpec {


Why aren't we using ToolSpec directly?

pakrym-oai

Cleaner! Please check the namespace deduplication comment that codex left. Sounds plausible.

pash-openai marked this pull request as ready for review April 17, 2026 23:50

pash-openai changed the title ~~Route self-namespaced dynamic tools~~ Add namespaces to dynamic tools Apr 18, 2026

pash-openai force-pushed the codex/fix-deferred-dynamic-tool-routing branch from 9d8f242 to ad75171 Compare April 18, 2026 01:41

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Comment thread codex-rs/core/src/tools/handlers/dynamic.rs Outdated

pash-openai marked this pull request as draft April 18, 2026 01:52

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Comment thread codex-rs/tools/src/tool_registry_plan.rs Outdated

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Comment thread codex-rs/app-server/src/codex_message_processor.rs

Comment thread codex-rs/app-server-protocol/src/protocol/v2.rs

pash-openai force-pushed the codex/fix-deferred-dynamic-tool-routing branch from 7b3d791 to 984d794 Compare April 18, 2026 20:42

pash-openai force-pushed the codex/fix-deferred-dynamic-tool-routing branch from 984d794 to d8411aa Compare April 18, 2026 20:47

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Comment thread codex-rs/tools/src/tool_registry_plan.rs Outdated

pash-openai force-pushed the codex/fix-deferred-dynamic-tool-routing branch 5 times, most recently from 9f7fd1f to b619c18 Compare April 18, 2026 22:22

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📊 AI CLI 工具社区动态日报 2026-04-19 gsscsd/big_model_radar#209

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pash-openai force-pushed the codex/fix-deferred-dynamic-tool-routing branch from b619c18 to 61927ed Compare April 19, 2026 04:29

Add namespaces to dynamic tools

7a8eb68

pash-openai force-pushed the codex/fix-deferred-dynamic-tool-routing branch from 61927ed to 7a8eb68 Compare April 19, 2026 04:36

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allow namespaces in code_mode + improvements to tests

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sayan-oai marked this pull request as ready for review April 20, 2026 23:16

sayan-oai requested a review from a team as a code owner April 20, 2026 23:16

sayan-oai added 2 commits April 20, 2026 16:18

clean up dynamic tool parsing

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Merge branch 'main' into codex/fix-deferred-dynamic-tool-routing

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Comment thread codex-rs/core/src/tools/tool_search_entry.rs Outdated

clean up dynamic -> toolspec conversion

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sayan-oai requested a review from pakrym-oai April 21, 2026 03:10

sayan-oai changed the title ~~Add namespaces to dynamic tools~~ Support namespaced deferred dynamic tools Apr 21, 2026

sayan-oai changed the title ~~Support namespaced deferred dynamic tools~~ [tool search] support namespaced deferred dynamic tools Apr 21, 2026

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clean up namespace separation

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	if name == "mcp" \|\| name.starts_with("mcp__") {
	return Err(format!("dynamic tool name is reserved: {name}"));
	}

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Review result: changes requested

1) P2 — namespace is optional in Rust/JSON Schema but required in generated TS

Notes on previously flagged items

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pash-openai commented Apr 17, 2026 •

edited by sayan-oai

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1) P2 — `namespace` is optional in Rust/JSON Schema but required in generated TS