feat(frontend): syntax-highlight all tool results + expand language support

[dimakis]

Summary

• All tool results now use CodeBlock instead of plain <pre> — Bash output gets bash highlighting, Write/Edit results use the file's language, everything else gets consistent monospace styling with copy button
• 12 new languages added to both CodeBlock registrations and EXT_MAP: clojure, dart, elixir, erlang, haskell, nginx, nix, objectivec, ocaml, powershell, scala, wasm
• Total language count: 34 → 46

Test plan

• Expand a Read tool pill → file content highlighted (unchanged behaviour)
• Expand a Bash tool pill → output highlighted with bash colouring
• Expand a Write tool pill → result section uses CodeBlock styling
• Expand an Edit/Diff tool pill → result section uses CodeBlock styling
• Expand a Grep/Glob tool pill → plain monospace in CodeBlock (no language)
• Read/Write/Edit a .nix, .ex, .hs, .dart, .scala file → correct highlighting

🤖 Generated with Claude Code

[dimakis]

Centaur Review

Found 5 issue(s) (1 critical) (3 warning).

frontend/src/components/__tests__/ToolPill.test.tsx

Broken existing test for non-read tool rendering is the critical issue; the code change itself is sound but needs test updates for the new behavior and new EXT_MAP entries, plus an nginx sync gap between CodeBlock registrations and EXT_MAP.

• 🔴 regressions (L177): Existing test 'renders plain pre for non-read tools' (lines 177-192) will fail. It asserts .tool-pill-pre exists and .code-block-highlight is null — but the new code renders all tool results through CodeBlock, which uses .code-block-highlight and never creates .tool-pill-pre. The test must be updated to match the new unified rendering. [fixable]

frontend/src/components/CodeBlock.tsx

Broken existing test for non-read tool rendering is the critical issue; the code change itself is sound but needs test updates for the new behavior and new EXT_MAP entries, plus an nginx sync gap between CodeBlock registrations and EXT_MAP.

• 🔵 style: nginx is imported and registered in CodeBlock but has no extension mapping in packages/protocol/src/language.ts EXT_MAP. The comment at line 8 says 'Keep in sync with EXT_MAP'. Without an EXT_MAP entry (e.g., conf: 'nginx'), no file will ever resolve to this language via languageFromPath. Either add an EXT_MAP entry or remove the nginx registration. [fixable]

packages/protocol/__tests__/language.test.ts

Broken existing test for non-read tool rendering is the critical issue; the code change itself is sound but needs test updates for the new behavior and new EXT_MAP entries, plus an nginx sync gap between CodeBlock registrations and EXT_MAP.

• 🟡 missing_tests: The 12 new EXT_MAP entries (objectivec, dart, scala, haskell, ocaml, clojure, elixir, erlang, powershell, nix, wasm, and multi-extension variants like .cljs/.edn/.lhs/.mli/.hrl/.psm1/.psd1/.wast) have no test coverage. The existing test file covers 15 extensions but none of the newly added ones. At minimum, add one representative test per new language. [fixable]

frontend/src/components/ToolPill.tsx

Broken existing test for non-read tool rendering is the critical issue; the code change itself is sound but needs test updates for the new behavior and new EXT_MAP entries, plus an nginx sync gap between CodeBlock registrations and EXT_MAP.

• 🟡 missing_tests: No test covers the new behavior where a non-read tool with a language (e.g., a Bash/command tool with language: 'bash') gets syntax highlighting via CodeBlock. The old test only covered the non-highlighted path. A test should verify that command-type tool results get bash highlighting and that Write-type results get their file-extension-derived highlighting. [fixable]
• 🟡 regressions (L93): Visual regression: non-read tool results previously rendered as a plain <pre> with a 'Result' <span> label (styled via .tool-pill-label + .tool-pill-pre). They now render inside a CodeBlock with a header bar containing label, copy button, and language badge. This changes the visual appearance — the header chrome (background, padding, copy button) will show even for simple one-line results like Grep output. Intentional UX change, but worth verifying it looks good for short/plain results.

[dimakis]

Centaur Review

Found 3 issue(s) (2 warning).

packages/protocol/src/language.ts

Clean feature expansion — EXT_MAP and CodeBlock registrations are in sync, the ToolResult refactor handles all edge cases correctly, and tests cover the core behavior. Main concern is .conf → nginx being overly broad.

• 🟡 unsafe_assumptions (L97): Mapping .conf → nginx is too broad. Many non-nginx files use .conf (e.g. httpd.conf for Apache, sysctl.conf, resolv.conf, logrotate.conf, application configs). Applying nginx syntax highlighting to these will produce misleading results. Consider removing this mapping or using basename-level detection (e.g. only match files containing 'nginx' in the name). [fixable]
• 🟡 unsafe_assumptions (L59): Mapping .m → objectivec conflicts with MATLAB/Octave, which also uses .m files. In codebases that use MATLAB, this will produce incorrect highlighting. No great solution — just worth documenting the ambiguity as a code comment.

packages/protocol/__tests__/language.test.ts

Clean feature expansion — EXT_MAP and CodeBlock registrations are in sync, the ToolResult refactor handles all edge cases correctly, and tests cover the core behavior. Main concern is .conf → nginx being overly broad.

• 🔵 missing_tests: New extension variants added to EXT_MAP lack test coverage: .mm (objectivec), .sbt (scala), .lhs (haskell), .mli (ocaml), .cljc/.edn (clojure), .exs (elixir), .hrl (erlang), .psm1/.psd1 (powershell), .wast (wasm). Each language has one extension tested but the secondary extensions are uncovered. [fixable]

[dimakis]

🟡 unsafe_assumptions: Mapping .conf → nginx is too broad. Many non-nginx files use .conf (e.g. httpd.conf for Apache, sysctl.conf, resolv.conf, logrotate.conf, application configs). Applying nginx syntax highlighting to these will produce misleading results. Consider removing this mapping or using basename-level detection (e.g. only match files containing 'nginx' in the name). [fixable]

[dimakis]

🟡 unsafe_assumptions: Mapping .m → objectivec conflicts with MATLAB/Octave, which also uses .m files. In codebases that use MATLAB, this will produce incorrect highlighting. No great solution — just worth documenting the ambiguity as a code comment.