StrucIn performs read-only static analysis on your repository:

• It reads Python files and parses their AST — it never executes your code.
• Analysis artifacts (JSON, Markdown) are written to the target repository directory.
• Cache files are stored in .strucin_cache/ within the target repository.

Python and documentation discovery skips file links that resolve outside the selected repository, dangling links, symlink loops, and non-regular files. Links to regular files inside the repository remain supported, with their repository-relative link paths preserved in analysis and search results. Directory links are not traversed during discovery.

Containment is rechecked whenever source or documentation bytes are read. On platforms supporting descriptor-relative opens and O_NOFOLLOW, path components are opened without following links to reject replacements between validation and reading. Other platforms use the validated canonical path. A file that becomes unsafe after discovery aborts that run instead of contributing outside content.

Search indexes produced before this policy are rebuilt by the CLI. Existing exports are not retroactively scrubbed; regenerate any previously shared analysis, reports, or indexes that may have included outside links.

Configured outputs and automatic caches must stay within the target repository. Parent-directory segments (..) and symlinks that resolve outside that directory are rejected before writing or cleaning up artifacts. All configured destinations are checked before cleanup deletes any stale files.

The explicit web --out /path/to/export option selects a separate dashboard output directory. Generated dashboard files are confined to that selected directory.

When using the explain command with an API key:

• A limited context (max 12,000 characters) of structural metadata is sent to the configured LLM provider (Anthropic or OpenAI).
• Secret redaction is applied before any LLM call — 9 regex patterns strip passwords, API keys, tokens, private keys, and credential URLs from the payload.
• No source code is sent — only module names, metrics, and docstrings.
• LLM calls are opt-in and require explicit API key configuration.

Enable safe mode for a repository with:

[security]
safe_mode = true

scan, analyze, report, explain, search, and web honor this setting. Each also accepts --safe-mode or --no-safe-mode to override it for one run. Pre-commit hooks honor the repository setting. diff operates on snapshots without loading repository configuration; use diff --safe-mode explicitly.

In safe mode:

• Generated index, analysis, graph, report, narration metadata, and dashboard contents hide repository paths, file paths, module/package names, import names, and class/function names. Graph relationships and numeric metrics remain.
• All docstrings and source snippets are omitted from shareable data. LLM context is anonymized before the provider call, including the repository root. Known identifiers and recognized secret patterns are filtered again from provider responses and cached narration before writing or returning them.
• Raw analysis caches are neither read nor written. Narration uses a separate .strucin_cache/explain_safe_cache.json containing filtered content. Normal explanation caches are never reused by safe mode.
• Search rebuilds its index in memory on every run, without reading or writing semantic_index.json. Results retain scores and line numbers with anonymous labels; source text and the query are omitted from displayed output.

Anonymous labels are scoped to an export and can change when the file set changes. For accurate comparisons, run diff --safe-mode on the original snapshots so matching happens before anonymization.

Safe mode governs newly generated content; it does not retroactively scrub older artifacts or caches. Existing retention cleanup still applies. Output filenames, configuration files, and diagnostic errors are not anonymized, so share the intended generated artifacts rather than the entire working directory or logs. Structural metrics and graph topology remain visible.

Library callers must pass safe_mode=True to the relevant output writer, report generator, explainer, or dashboard builder. Raw analyze_repository results remain in memory with original names; use use_cache=False to prevent raw cache reads and writes. The low-level semantic index writer persists source text and should not be used for a safe export.

If you discover a security vulnerability in StrucIn, please report it responsibly:

1. Do not open a public GitHub issue.
2. Email contact@macitch.dev with:
   • A description of the vulnerability
   • Steps to reproduce
   • Affected version(s)
3. You will receive an acknowledgment within 48 hours.
4. A fix will be prioritized and released as a patch version.

The following are in scope for security reports:

• Secret leakage through LLM calls or output artifacts
• Path traversal in file scanning or artifact writing
• Code execution through crafted Python files (AST parsing should never execute code)
• Dependency vulnerabilities in core dependencies

The following are out of scope:

• Denial of service through extremely large repositories (expected behavior)
• Issues requiring physical access to the machine running StrucIn