Compatibility of MCP tool with Codex CLI

[jskorlol]

I wanted to ask about the compatibility of the MCP tool with Codex CLI.

Currently, I’ve been running into performance issues with Claude Code, so I’ve switched to using Codex CLI more frequently. My concern is whether the MCP tool will continue to work without issues in Codex CLI, given that some parts of the prompt still contain references to Claude.

Is there any limitation or risk of degraded performance when using the MCP tool in Codex CLI instead of Claude Code? Over time, I may end up using Codex CLI exclusively, so I’d like to confirm future compatibility.

Thanks!

[bartolli]

I wanted to ask about the compatibility of the MCP tool with Codex CLI.

Currently, I’ve been running into performance issues with Claude Code, so I’ve switched to using Codex CLI more frequently. My concern is whether the MCP tool will continue to work without issues in Codex CLI, given that some parts of the prompt still contain references to Claude.

Is there any limitation or risk of degraded performance when using the MCP tool in Codex CLI instead of Claude Code? Over time, I may end up using Codex CLI exclusively, so I’d like to confirm future compatibility.

Thanks!

Hey, sorry for my late reply.

Yes, Codanna works with Codex CLI. It's a standard MCP server, not tied to any specific client.

Here's the configuration for ~/.codex/config.toml:

[mcp_servers.codanna]
command = "/Users/yourusername/.cargo/bin/codanna"
args = ["serve", "--watch"]
startup_timeout_ms = 20000

For your AGENTS.md or system prompt:

## Codanna MCP Tools

Workflow:
1. semantic_search_with_context - Find relevant code with context
2. analyze_impact - Map dependencies and change radius
3. find_symbol, get_calls, find_callers - Get specific details

Tool priority:
- Tier 1: semantic_search_with_context, analyze_impact
- Tier 2: find_symbol, get_calls, find_callers
- Tier 3: search_symbols, semantic_search_docs, get_index_info

Start with semantic search, then narrow with specific queries.

The references to claude in our docs are just examples - the MCP protocol works the same way in any client. No compatibility issues with codex cli.

Let me know if you run into any issues!

[jskorlol]

Thanks!

[jskorlol]

[mcp_servers.codanna]
command = "codanna"
args = ["serve", "--watch"]
startup_timeout_ms = 20_000

• Server: codanna
    • Command: codanna serve --watch
    • Tools: analyze_impact, find_callers, find_symbol, get_calls, get_index_info, search_symbols, semantic_search_docs, semantic_search_with_context

Called codanna.semantic_search_with_context({"query":"prompt manager service prompt selection","limit":5,"lang":"typescript"})
  └ Semantic search failed: Semantic search failed: No embeddings available for search

It seems like even though I’ve configured codanna, the MCP tool doesn’t automatically start indexing.

How can I actually use it within my project in Codex?
Has codanna init become a required command now?
I’m pretty sure everything used to be automatic before.

[bartolli]

Hey @jskorlol

The MCP server (codanna serve) doesn't automatically index your codebase.. it serves an existing index. You need to build the index first:

# Initialize configuration (first time only)
codanna init

# Build the index for your project
codanna index .

After indexing completes, the MCP server will be able to access it. The --watch flag monitors for file changes but still requires an initial index.

Order of operations:

1. codanna init - Creates .codanna/ configuration (one-time setup)
2. codanna index . - Builds searchable index from your codebase
3. MCP server connects and serves the index

You can index specific directories with codanna index src or re-index anytime with codanna index . --force.
Let me know if you still have any problems, happy to help.

[jskorlol]

Ah, it seems things used to work automatically when you just connected and ran mcp, but there must have been some changes along the way.
From now on, I’ll make sure to execute that command for every project.

Thanks!