Codex env_http_headers reverses header names and environment variable names

[mishamilovidov]

Summary

The Codex target writes env_http_headers entries in the wrong direction.

Codex expects each HTTP header name as a key. Its value must be the name of an environment variable.

Reproduction

Add an HTTP MCP server with a symbolic header value:

[[mcp]]
name = "example"
url = "https://example.test/mcp"

[mcp.headers]
X-Api-Key = "${API_KEY}"

Run dotagents install, then inspect the generated Codex configuration.

Actual result

DotAgents maps the environment variable name to the HTTP header name:

env_http_headers.API_KEY = "X-Api-Key"

Codex interprets API_KEY as the HTTP header name and X-Api-Key as the environment variable name. Authentication then fails.

Expected result

DotAgents must map the HTTP header name to the environment variable name:

env_http_headers.X-Api-Key = "API_KEY"

Implementation notes

The affected helper is extractCodexHeaders in packages/dotagents/src/targets/definitions/helpers.ts.

Focused tests exist in:

• packages/dotagents/src/targets/definitions/helpers.test.ts
• packages/dotagents/src/targets/mcp-writer.test.ts

This problem is related to #158 because both defects affect symbolic environment references in Codex configuration. Issue 158 covers stdio env_vars. This issue covers HTTP env_http_headers and uses a different code path.

Environment

• DotAgents 3.0.1
• Codex 0.147.0 and 0.149.0