René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Restore configurable simulator OSLog subsystem filters","articleBody":"## Problem\n\n`build_run_sim` and `launch_app_sim` currently start OSLog capture with a fixed predicate:\n\n```text\nsubsystem == \"\u003cbundleId\u003e\"\n```\n\nThat means simulator run flows no longer expose the older log-capture behavior that allowed callers to broaden or customize the subsystem filter (for example app-only vs SwiftUI vs custom subsystems vs all logs). This is a regression for users who need runtime logs outside the app bundle ID subsystem.\n\n## Current behavior\n\n- `build_run_sim` extracts the app bundle ID from the built app and passes it to `launchSimulatorAppWithLogging`.\n- `launch_app_sim` accepts a user-provided `bundleId` and passes it to `launchSimulatorAppWithLogging`.\n- `launchSimulatorAppWithLogging` validates `bundleId`, then `startTrackedOsLogStream` builds the fixed OSLog predicate using that bundle ID.\n- There is no public tool argument for custom subsystem filters or broader OSLog capture.\n\n## Expected behavior\n\nExpose a public, structured option for simulator OSLog filtering so callers can request useful non-default capture modes without raw predicate injection risk.\n\nSuggested shape, matching the old intent:\n\n```ts\nsubsystemFilter?: 'app' | 'all' | 'swiftui' | string[];\n```\n\nSemantics:\n\n- `app`: current default, `subsystem == \"\u003cbundleId\u003e\"`\n- `all`: omit `--predicate`\n- `swiftui`: include app subsystem and `com.apple.SwiftUI`\n- `string[]`: include app subsystem plus caller-provided subsystem names\n\n## Security requirement\n\nPR #407 reintroduced validation for the current fixed predicate by validating `bundleId` before it is interpolated into:\n\n```text\n--predicate subsystem == \"\u003cbundleId\u003e\"\n```\n\nIf custom filter arguments are added, the same validation needs to be applied at the predicate-construction boundary:\n\n- Validate `bundleId`.\n- Validate every caller-provided subsystem string.\n- Allow only alphanumeric characters, dots, hyphens, and underscores.\n- Reject invalid values before spawning any `simctl launch` or `log stream` helper.\n- Do not expose raw NSPredicate strings unless there is a separate security model for arbitrary predicate syntax.\n\n## Acceptance criteria\n\n- `build_run_sim` and `launch_app_sim` expose the same OSLog filter option.\n- Invalid subsystem values return structured tool failures before spawning helpers.\n- Structured output includes a diagnostic explaining the invalid filter value.\n- Tests cover quotes/backslashes/predicate operators in both bundle ID and custom subsystem filter values.\n- Default behavior remains unchanged: app subsystem only.\n","author":{"url":"https://github.com/cameroncooke","@type":"Person","name":"cameroncooke"},"datePublished":"2026-05-11T08:57:41.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/409/XcodeBuildMCP/issues/409"}