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lean_ctx/hooks/agents/
codex.rs

1use super::super::{
2    ensure_codex_hooks_enabled as shared_ensure_codex_hooks_enabled, ensure_state_dir,
3    install_codex_instruction_docs, mcp_server_quiet_mode, resolve_binary_path,
4    upsert_lean_ctx_codex_hook_entries, write_file,
5};
6
7pub fn install_codex_hook() {
8    let Some(codex_dir) = crate::core::home::resolve_codex_dir() else {
9        tracing::error!("Cannot resolve codex directory");
10        return;
11    };
12    if !ensure_state_dir(&codex_dir) {
13        return;
14    }
15
16    let hook_config_changed = install_codex_hook_config(&codex_dir);
17    let installed_docs = install_codex_instruction_docs(&codex_dir);
18
19    if !mcp_server_quiet_mode() {
20        if hook_config_changed {
21            eprintln!(
22                "Installed Codex-compatible SessionStart/PreToolUse hooks at {}",
23                codex_dir.display()
24            );
25        }
26        if installed_docs {
27            eprintln!("Installed Codex instructions at {}", codex_dir.display());
28        } else {
29            eprintln!("Codex AGENTS.md already configured.");
30        }
31    }
32}
33
34fn install_codex_hook_config(codex_dir: &std::path::Path) -> bool {
35    let binary = resolve_binary_path();
36    let session_start_cmd = format!("{binary} hook codex-session-start");
37    let pre_tool_use_cmd = format!("{binary} hook codex-pretooluse");
38    let hooks_json_path = codex_dir.join("hooks.json");
39
40    let mut changed = false;
41    let mut root = if hooks_json_path.exists() {
42        if let Some(parsed) = std::fs::read_to_string(&hooks_json_path)
43            .ok()
44            .and_then(|content| crate::core::jsonc::parse_jsonc(&content).ok())
45        {
46            parsed
47        } else {
48            changed = true;
49            serde_json::json!({ "hooks": {} })
50        }
51    } else {
52        changed = true;
53        serde_json::json!({ "hooks": {} })
54    };
55
56    if upsert_lean_ctx_codex_hook_entries(&mut root, &session_start_cmd, &pre_tool_use_cmd) {
57        changed = true;
58    }
59
60    // Observe hooks for context awareness
61    let observe_cmd = format!("{binary} hook observe");
62    if ensure_codex_observe_hooks(&mut root, &observe_cmd) {
63        changed = true;
64    }
65
66    if changed {
67        write_file(
68            &hooks_json_path,
69            &serde_json::to_string_pretty(&root).unwrap_or_default(),
70        );
71    }
72
73    let rewrite_path = codex_dir.join("hooks").join("lean-ctx-rewrite-codex.sh");
74    if rewrite_path.exists() && std::fs::remove_file(&rewrite_path).is_ok() {
75        changed = true;
76    }
77
78    let config_toml_path = codex_dir.join("config.toml");
79    let config_content = std::fs::read_to_string(&config_toml_path).unwrap_or_default();
80
81    // Hybrid mode: ensure MCP server entry exists in config.toml so Codex
82    // Desktop/Cloud can reach lean-ctx even without CLI hooks.
83    let mcp_updated = ensure_codex_mcp_server(
84        &config_content,
85        &binary,
86        &super::super::mcp_server_env_pairs(),
87    );
88    let hooks_updated =
89        ensure_codex_hooks_enabled(mcp_updated.as_deref().unwrap_or(&config_content));
90
91    let final_content = hooks_updated
92        .or(mcp_updated)
93        .unwrap_or_else(|| config_content.clone());
94    if final_content != config_content {
95        write_file(&config_toml_path, &final_content);
96        changed = true;
97        if !mcp_server_quiet_mode() {
98            eprintln!(
99                "Updated Codex config (MCP server + hooks) in {}",
100                config_toml_path.display()
101            );
102        }
103    }
104
105    changed
106}
107
108fn ensure_codex_observe_hooks(root: &mut serde_json::Value, observe_cmd: &str) -> bool {
109    let original = root.clone();
110    let Some(hooks_obj) = root
111        .as_object_mut()
112        .and_then(|r| r.get_mut("hooks"))
113        .and_then(|h| h.as_object_mut())
114    else {
115        return false;
116    };
117
118    let observe_events = ["PostToolUse", "SessionStart", "SessionEnd"];
119    for event in observe_events {
120        let arr = hooks_obj
121            .entry(event.to_string())
122            .or_insert_with(|| serde_json::json!([]));
123        let Some(entries) = arr.as_array_mut() else {
124            continue;
125        };
126        let already = entries.iter().any(|e| {
127            e.get("hooks")
128                .and_then(|h| h.as_array())
129                .is_some_and(|hooks| {
130                    hooks.iter().any(|hook| {
131                        hook.get("command")
132                            .and_then(|c| c.as_str())
133                            .is_some_and(|c| c.contains("hook observe"))
134                    })
135                })
136        });
137        if !already {
138            entries.push(serde_json::json!({
139                "matcher": ".*",
140                "hooks": [{ "type": "command", "command": observe_cmd, "timeout": 5 }]
141            }));
142        }
143    }
144
145    *root != original
146}
147
148/// Idempotent upsert of the `[mcp_servers.lean-ctx]` entry in Codex `config.toml`.
149///
150/// Uses a format-preserving TOML editor so existing user content/comments and an
151/// orphaned `[mcp_servers.lean-ctx.env]` (issue #189) are normalized into a
152/// single valid section instead of producing a duplicate table header.
153///
154/// `env_pairs` is injected (not read from global state) so the pure
155/// config-rewriting logic is hermetically testable; the caller passes
156/// [`crate::hooks::mcp_server_env_pairs`]. Existing `command`/`args` are left
157/// untouched to respect user customization; env keys are upserted so a stale
158/// install gains `LEAN_CTX_PROJECT_ROOT`/`LEAN_CTX_EXTRA_ROOTS` (#403). Returns
159/// `None` when nothing changed, or when the file is not valid TOML (never
160/// clobbers an unparseable user config).
161fn ensure_codex_mcp_server(
162    config_content: &str,
163    binary: &str,
164    env_pairs: &[(String, String)],
165) -> Option<String> {
166    let mut doc = config_content.parse::<toml_edit::DocumentMut>().ok()?;
167    let original = doc.to_string();
168
169    // `[mcp_servers]` stays implicit so we never emit a bare parent header.
170    let servers = doc["mcp_servers"].or_insert(toml_edit::table());
171    if let Some(t) = servers.as_table_mut() {
172        t.set_implicit(true);
173    }
174
175    // `[mcp_servers.lean-ctx]` must be explicit so its header is rendered before
176    // the `.env` child table (fixes the orphaned-env ordering from #189).
177    let lean = servers["lean-ctx"].or_insert(toml_edit::table());
178    let lean_tbl = lean.as_table_mut()?;
179    lean_tbl.set_implicit(false);
180
181    // Respect user customization: only fill `command`/`args` when absent.
182    if !lean_tbl.contains_key("command") {
183        lean_tbl["command"] = toml_edit::value(binary);
184    }
185    if !lean_tbl.contains_key("args") {
186        lean_tbl["args"] = toml_edit::value(toml_edit::Array::new());
187    }
188
189    let env = lean_tbl["env"].or_insert(toml_edit::table());
190    if let Some(env_tbl) = env.as_table_mut() {
191        for (key, val) in env_pairs {
192            let key = key.as_str();
193            if env_tbl.get(key).and_then(toml_edit::Item::as_str) != Some(val.as_str()) {
194                env_tbl[key] = toml_edit::value(val.as_str());
195            }
196        }
197    }
198
199    let updated = doc.to_string();
200    (updated != original).then_some(updated)
201}
202
203fn ensure_codex_hooks_enabled(config_content: &str) -> Option<String> {
204    shared_ensure_codex_hooks_enabled(config_content)
205}
206
207#[cfg(test)]
208mod tests {
209    use super::{
210        ensure_codex_hooks_enabled, ensure_codex_mcp_server, upsert_lean_ctx_codex_hook_entries,
211    };
212    use serde_json::json;
213
214    /// Minimal env block (data dir only) for the config-rewrite tests that do
215    /// not exercise project-root/extra-roots propagation.
216    fn data_dir_pairs() -> Vec<(String, String)> {
217        vec![(
218            "LEAN_CTX_DATA_DIR".to_string(),
219            "/Users/user/.lean-ctx".to_string(),
220        )]
221    }
222
223    #[test]
224    fn upsert_replaces_legacy_codex_rewrite_but_keeps_custom_hooks() {
225        let mut input = json!({
226            "hooks": {
227                "PreToolUse": [
228                    {
229                        "matcher": "Bash",
230                        "hooks": [{
231                            "type": "command",
232                            "command": "/opt/homebrew/bin/lean-ctx hook rewrite",
233                            "timeout": 15
234                        }]
235                    },
236                    {
237                        "matcher": "Bash",
238                        "hooks": [{
239                            "type": "command",
240                            "command": "echo keep-me",
241                            "timeout": 5
242                        }]
243                    }
244                ],
245                "SessionStart": [
246                    {
247                        "matcher": "startup|resume|clear",
248                        "hooks": [{
249                            "type": "command",
250                            "command": "lean-ctx hook codex-session-start",
251                            "timeout": 15
252                        }]
253                    }
254                ],
255                "PostToolUse": [
256                    {
257                        "matcher": "Bash",
258                        "hooks": [{
259                            "type": "command",
260                            "command": "echo keep-post",
261                            "timeout": 5
262                        }]
263                    }
264                ]
265            }
266        });
267
268        let changed = upsert_lean_ctx_codex_hook_entries(
269            &mut input,
270            "lean-ctx hook codex-session-start",
271            "lean-ctx hook codex-pretooluse",
272        );
273        assert!(changed, "legacy hooks should be migrated");
274
275        let pre_tool_use = input["hooks"]["PreToolUse"]
276            .as_array()
277            .expect("PreToolUse array should remain");
278        assert_eq!(pre_tool_use.len(), 2, "custom hook should be preserved");
279        assert_eq!(
280            pre_tool_use[0]["hooks"][0]["command"].as_str(),
281            Some("echo keep-me")
282        );
283        assert_eq!(
284            pre_tool_use[1]["hooks"][0]["command"].as_str(),
285            Some("lean-ctx hook codex-pretooluse")
286        );
287        assert_eq!(
288            input["hooks"]["SessionStart"][0]["hooks"][0]["command"].as_str(),
289            Some("lean-ctx hook codex-session-start")
290        );
291        assert_eq!(
292            input["hooks"]["PostToolUse"][0]["hooks"][0]["command"].as_str(),
293            Some("echo keep-post")
294        );
295    }
296
297    #[test]
298    fn ignores_non_lean_ctx_codex_entries() {
299        let custom = json!({
300            "matcher": "Bash",
301            "hooks": [{
302                "type": "command",
303                "command": "echo keep-me",
304                "timeout": 5
305            }]
306        });
307        assert!(
308            !crate::hooks::support::is_lean_ctx_codex_managed_entry("PreToolUse", &custom),
309            "custom Codex hooks must be preserved"
310        );
311    }
312
313    #[test]
314    fn detects_managed_codex_session_start_entry() {
315        let managed = json!({
316            "matcher": "startup|resume|clear",
317            "hooks": [{
318                "type": "command",
319                "command": "/opt/homebrew/bin/lean-ctx hook codex-session-start",
320                "timeout": 15
321            }]
322        });
323        assert!(crate::hooks::support::is_lean_ctx_codex_managed_entry(
324            "SessionStart",
325            &managed
326        ));
327    }
328
329    #[test]
330    fn ensure_codex_hooks_enabled_updates_existing_features_flag() {
331        let input = "\
332[features]
333other = true
334codex_hooks = false
335
336[mcp_servers.other]
337command = \"other\"
338";
339
340        let output =
341            ensure_codex_hooks_enabled(input).expect("codex_hooks=false should be migrated");
342
343        assert!(output.contains("[features]\nother = true\nhooks = true\n"));
344        assert!(!output.contains("codex_hooks = false"));
345    }
346
347    #[test]
348    fn ensure_codex_hooks_enabled_moves_stray_assignment_into_features_section() {
349        let input = "\
350[features]
351other = true
352
353[mcp_servers.lean-ctx]
354command = \"lean-ctx\"
355codex_hooks = true
356";
357
358        let output = ensure_codex_hooks_enabled(input)
359            .expect("stray codex_hooks assignment should be normalized");
360
361        assert!(output.contains("[features]\nother = true\nhooks = true\n"));
362        assert_eq!(output.matches("hooks = true").count(), 1);
363        assert!(!output.contains("[mcp_servers.lean-ctx]\ncommand = \"lean-ctx\"\nhooks = true"));
364    }
365
366    #[test]
367    fn ensure_codex_hooks_enabled_adds_features_section_when_missing() {
368        let input = "\
369[mcp_servers.lean-ctx]
370command = \"lean-ctx\"
371";
372
373        let output =
374            ensure_codex_hooks_enabled(input).expect("missing features section should be added");
375
376        assert!(output.ends_with("\n[features]\nhooks = true\n"));
377    }
378
379    #[test]
380    fn codex_docs_steer_to_reliable_mcp_path_without_false_hook_claim() {
381        let tmp = std::env::temp_dir().join("lean-ctx-test-codex-desktop-note");
382        let _ = std::fs::remove_dir_all(&tmp);
383        std::fs::create_dir_all(&tmp).unwrap();
384
385        crate::hooks::support::install_codex_instruction_docs(&tmp);
386
387        let lean_ctx_md = std::fs::read_to_string(tmp.join("LEAN-CTX.md")).unwrap();
388        assert!(
389            lean_ctx_md.contains("ctx_shell") && lean_ctx_md.contains("ctx_read"),
390            "LEAN-CTX.md must steer the agent to the MCP tools"
391        );
392        // Regression guard for #350: never assert as fact that Desktop/Cloud hooks
393        // do not run — they can (gated by trust via /hooks, varies by version).
394        let normalized = lean_ctx_md.replace('\n', " ");
395        assert!(
396            !normalized.contains("hooks do not run")
397                && !normalized.contains("no automatic compression"),
398            "LEAN-CTX.md must not make the false blanket claim that Codex Desktop hooks never run (#350)"
399        );
400
401        let agents_md = std::fs::read_to_string(tmp.join("AGENTS.md")).unwrap();
402        assert!(
403            agents_md.contains("ctx_shell") && agents_md.contains("ctx_search"),
404            "AGENTS.md block must steer to the reliable MCP tools"
405        );
406        let agents_norm = agents_md.replace('\n', " ");
407        assert!(
408            !agents_norm.contains("hooks do not run"),
409            "AGENTS.md must not claim Codex hooks never run (#350)"
410        );
411
412        let _ = std::fs::remove_dir_all(&tmp);
413    }
414
415    #[test]
416    fn install_codex_docs_preserves_existing_user_instructions() {
417        let tmp = std::env::temp_dir().join("lean-ctx-test-codex-preserve");
418        let _ = std::fs::remove_dir_all(&tmp);
419        std::fs::create_dir_all(&tmp).unwrap();
420
421        let agents_md = tmp.join("AGENTS.md");
422        let user_content = "# My Custom Instructions\n\nDo not change my codebase style.\n\n## Rules\n- Always use tabs\n- No semicolons\n";
423        std::fs::write(&agents_md, user_content).unwrap();
424
425        crate::hooks::support::install_codex_instruction_docs(&tmp);
426
427        let result = std::fs::read_to_string(&agents_md).unwrap();
428        assert!(
429            result.contains("My Custom Instructions"),
430            "user content must be preserved"
431        );
432        assert!(
433            result.contains("Always use tabs"),
434            "user rules must be preserved"
435        );
436        assert!(
437            result.contains(crate::core::rules_canonical::AGENTS_BLOCK_START),
438            "lean-ctx block must be appended"
439        );
440        let expected_ref = tmp.join("LEAN-CTX.md").display().to_string();
441        assert!(
442            result.contains(&expected_ref),
443            "lean-ctx reference must use codex_dir path"
444        );
445
446        let _ = std::fs::remove_dir_all(&tmp);
447    }
448
449    #[test]
450    fn install_codex_docs_updates_only_marked_block() {
451        let tmp = std::env::temp_dir().join("lean-ctx-test-codex-marked");
452        let _ = std::fs::remove_dir_all(&tmp);
453        std::fs::create_dir_all(&tmp).unwrap();
454
455        let agents_md = tmp.join("AGENTS.md");
456        let content_with_block = format!(
457            "# My Instructions\n\nCustom rule here.\n\n{}\n## lean-ctx\n\n@OLD-LEAN-CTX.md\n{}\n\n## Other Section\nKeep this.\n",
458            crate::core::rules_canonical::AGENTS_BLOCK_START,
459            crate::core::rules_canonical::AGENTS_BLOCK_END,
460        );
461        std::fs::write(&agents_md, content_with_block).unwrap();
462
463        crate::hooks::support::install_codex_instruction_docs(&tmp);
464
465        let result = std::fs::read_to_string(&agents_md).unwrap();
466        assert!(
467            result.contains("Custom rule here."),
468            "user content before block preserved"
469        );
470        assert!(
471            result.contains("Other Section"),
472            "user content after block preserved"
473        );
474        let expected_ref = tmp.join("LEAN-CTX.md").display().to_string();
475        assert!(
476            result.contains(&expected_ref),
477            "block updated to current reference"
478        );
479        assert!(
480            !result.contains("OLD-LEAN-CTX"),
481            "old block content replaced"
482        );
483
484        let _ = std::fs::remove_dir_all(&tmp);
485    }
486
487    #[test]
488    fn ensure_mcp_server_adds_section_when_missing() {
489        let input = "[features]\ncodex_hooks = true\n";
490        let result = ensure_codex_mcp_server(input, "lean-ctx", &data_dir_pairs())
491            .expect("should add MCP section");
492        assert!(result.contains("[mcp_servers.lean-ctx]"));
493        assert!(result.contains("command = \"lean-ctx\""));
494        assert!(result.contains("args = []"));
495        assert!(result.contains("[features]\ncodex_hooks = true\n"));
496    }
497
498    #[test]
499    fn ensure_mcp_server_noop_when_already_complete() {
500        // Parent + args + an env block already carrying every desired key: the
501        // upsert must be a true no-op (no churn on every session start).
502        let input = "[mcp_servers.lean-ctx]\ncommand = \"lean-ctx\"\nargs = []\n\n\
503                     [mcp_servers.lean-ctx.env]\nLEAN_CTX_DATA_DIR = \"/Users/user/.lean-ctx\"\n";
504        assert!(
505            ensure_codex_mcp_server(input, "lean-ctx", &data_dir_pairs()).is_none(),
506            "should not modify config when MCP section already has all keys"
507        );
508    }
509
510    #[test]
511    fn ensure_mcp_server_preserves_existing_sections() {
512        let input = "[mcp_servers.other]\ncommand = \"other\"\n";
513        let result = ensure_codex_mcp_server(input, "/usr/bin/lean-ctx", &data_dir_pairs())
514            .expect("should add lean-ctx section");
515        assert!(result.contains("[mcp_servers.other]"));
516        assert!(result.contains("[mcp_servers.lean-ctx]"));
517        assert!(result.contains("command = \"/usr/bin/lean-ctx\""));
518    }
519
520    #[test]
521    fn ensure_mcp_server_inserts_before_orphaned_env_subtable() {
522        let input = "\
523[mcp_servers.lean-ctx.env]
524LEAN_CTX_DATA_DIR = \"/Users/user/.lean-ctx\"
525";
526        let result = ensure_codex_mcp_server(input, "/usr/local/bin/lean-ctx", &data_dir_pairs())
527            .expect("should insert parent section before orphaned env");
528        let parent_pos = result
529            .find("[mcp_servers.lean-ctx]")
530            .expect("parent section must exist");
531        let env_pos = result
532            .find("[mcp_servers.lean-ctx.env]")
533            .expect("env sub-table must be preserved");
534        assert!(
535            parent_pos < env_pos,
536            "parent section must come before env sub-table"
537        );
538        assert!(result.contains("command = \"/usr/local/bin/lean-ctx\""));
539        assert!(result.contains("LEAN_CTX_DATA_DIR"));
540        assert_eq!(
541            result.matches("[mcp_servers.lean-ctx.env]").count(),
542            1,
543            "must not duplicate the env table (would be invalid TOML)"
544        );
545    }
546
547    #[test]
548    fn ensure_mcp_server_handles_issue_189_scenario() {
549        let input = "\
550source = \"/Users/user/.cache/codex-runtimes/codex-primary-runtime/plugins/openai-primary-runtime\"
551source_type = \"local\"
552
553[mcp_servers.lean-ctx.env]
554LEAN_CTX_DATA_DIR = \"/Users/user/.lean-ctx\"
555";
556        let result = ensure_codex_mcp_server(input, "/usr/local/bin/lean-ctx", &data_dir_pairs())
557            .expect("should fix orphaned config from issue #189");
558        assert!(result.contains("[mcp_servers.lean-ctx]\n"));
559        assert!(result.contains("command = \"/usr/local/bin/lean-ctx\""));
560        assert!(result.contains("[mcp_servers.lean-ctx.env]"));
561        assert!(result.contains("LEAN_CTX_DATA_DIR"));
562
563        let parent_pos = result.find("[mcp_servers.lean-ctx]\n").unwrap();
564        let env_pos = result.find("[mcp_servers.lean-ctx.env]").unwrap();
565        assert!(parent_pos < env_pos);
566        assert_eq!(
567            result.matches("[mcp_servers.lean-ctx.env]").count(),
568            1,
569            "issue #189 fix must merge into one env table, not duplicate it"
570        );
571        // Original sibling content must survive the normalization.
572        assert!(result.contains("source_type = \"local\""));
573    }
574
575    #[test]
576    fn ensure_mcp_server_quotes_windows_backslash_paths() {
577        let input = "[features]\ncodex_hooks = true\n";
578        let win_path = r"C:\Users\Foo\AppData\Roaming\npm\lean-ctx.cmd";
579        let result = ensure_codex_mcp_server(input, win_path, &data_dir_pairs())
580            .expect("should add MCP section");
581        // Quote style is the TOML editor's concern; what matters is that the
582        // backslash path round-trips to exactly the same string and stays valid.
583        let doc = result
584            .parse::<toml_edit::DocumentMut>()
585            .expect("output must be valid TOML");
586        assert_eq!(
587            doc["mcp_servers"]["lean-ctx"]["command"].as_str(),
588            Some(win_path),
589            "Windows backslash path must round-trip exactly: {result}"
590        );
591    }
592
593    #[test]
594    fn ensure_mcp_server_does_not_match_similarly_named_section() {
595        let input = "\
596[mcp_servers.lean-ctx-other]
597command = \"other\"
598";
599        let result = ensure_codex_mcp_server(input, "lean-ctx", &data_dir_pairs())
600            .expect("should add lean-ctx section despite similarly-named section");
601        assert!(result.contains("[mcp_servers.lean-ctx]\n"));
602        assert!(result.contains("[mcp_servers.lean-ctx-other]"));
603    }
604
605    #[test]
606    fn ensure_mcp_server_writes_project_and_extra_roots() {
607        // #403: when init captured a project root + sibling worktrees, those
608        // must be propagated into the env block so the long-lived MCP server
609        // resolves explicit paths under every root.
610        let pairs = vec![
611            (
612                "LEAN_CTX_DATA_DIR".to_string(),
613                "/home/u/.lean-ctx".to_string(),
614            ),
615            (
616                "LEAN_CTX_PROJECT_ROOT".to_string(),
617                "/work/main".to_string(),
618            ),
619            (
620                "LEAN_CTX_EXTRA_ROOTS".to_string(),
621                "/work/wt-a:/work/wt-b".to_string(),
622            ),
623        ];
624        let result =
625            ensure_codex_mcp_server("", "lean-ctx", &pairs).expect("fresh config must be created");
626
627        let doc = result
628            .parse::<toml_edit::DocumentMut>()
629            .expect("output must be valid TOML");
630        let env = &doc["mcp_servers"]["lean-ctx"]["env"];
631        assert_eq!(env["LEAN_CTX_PROJECT_ROOT"].as_str(), Some("/work/main"));
632        assert_eq!(
633            env["LEAN_CTX_EXTRA_ROOTS"].as_str(),
634            Some("/work/wt-a:/work/wt-b")
635        );
636        assert_eq!(env["LEAN_CTX_DATA_DIR"].as_str(), Some("/home/u/.lean-ctx"));
637    }
638
639    #[test]
640    fn ensure_mcp_server_upserts_missing_keys_into_existing_env() {
641        // Pre-existing install (only DATA_DIR) must gain the new roots without
642        // duplicating the section, and the operation must be idempotent.
643        let input = "[mcp_servers.lean-ctx]\ncommand = \"lean-ctx\"\nargs = []\n\n\
644                     [mcp_servers.lean-ctx.env]\nLEAN_CTX_DATA_DIR = \"/home/u/.lean-ctx\"\n";
645        let pairs = vec![
646            (
647                "LEAN_CTX_DATA_DIR".to_string(),
648                "/home/u/.lean-ctx".to_string(),
649            ),
650            (
651                "LEAN_CTX_PROJECT_ROOT".to_string(),
652                "/work/main".to_string(),
653            ),
654        ];
655
656        let result = ensure_codex_mcp_server(input, "lean-ctx", &pairs)
657            .expect("should upsert the missing project root");
658        assert_eq!(
659            result.matches("[mcp_servers.lean-ctx]").count(),
660            1,
661            "must not duplicate the parent section"
662        );
663        let doc = result
664            .parse::<toml_edit::DocumentMut>()
665            .expect("output must be valid TOML");
666        assert_eq!(
667            doc["mcp_servers"]["lean-ctx"]["env"]["LEAN_CTX_PROJECT_ROOT"].as_str(),
668            Some("/work/main")
669        );
670
671        // Second pass over the upserted config is a no-op.
672        assert!(
673            ensure_codex_mcp_server(&result, "lean-ctx", &pairs).is_none(),
674            "upsert must be idempotent"
675        );
676    }
677}