io.github.heuristicolab/ctxfw
PYPI · CTXFW
Zero-egress AI Agent Firewall: SARA prompt injection defense, AST context pruning & MCP governance.
Available components
Last scanned (14 hours ago)
Scores higher than 67% of PyPI servers
Category Testing and QA
How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score → Why this is hard to score →
Supply Chain Security100
- No malware found by supply-chain analysis.Pass
- No known CVEs affecting this package version or its production dependencies.Pass
- Runs hatchling.build at install time, a recognised build step with no custom scripting around it. View diagnostics → Pass
- 1 of 11 dependencies flagged as unhealthy. View diagnostics → Partial
Provenance & Transparency45
- Source repository is publicly reachable at the declared URL. View diagnostics → Pass
- Provenance check failed: no build-provenance attestation is published. See how to fix → View diagnostics → Fail
- Clear OSI-approved license (Apache-2.0).Pass
- Actively maintained (last published 10 days ago).Pass
- Disclosure check failed: no security disclosure policy was found in the source repository. See how to fix → Fail
Schema Quality & AI Usability63
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 1186 tokens (~237/item across 5 items; 5 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management37
- Stability observed for 11 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
- Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 5 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 6 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities20
- Spec-recency check failed: implements MCP spec 2024-11-05; the latest is 2026-07-28. See how to fix → Fail
Checks we ran (16)
- Malware scan
- Known CVEs
- Install scripts
- Dependency health
- Source repository
- Provenance
- License
- Maintenance
- Security disclosure
- Schema quality
- Stability
- Tool coverage
- Injection markers
- Destructive annotations
- Judged manipulation
- MCP protocol
Does not apply to this package (2)
- Endpoint SecurityScored on hosted endpoints only. A package has no live endpoint of its own for us to probe.
- Transport & ReachabilityScored on hosted endpoints only. A package has no live endpoint of its own for us to probe.
The score does not measure everything. What the score does not measure →
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 4 Nov 26 +16
- Malware scan: unverified → pass ▲ security
- 3 Nov 26 −15
- Malware scan: pass → unverified ▼ security
- 2 Nov 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.
- 1 Nov 26 +15
- Malware scan: unverified → pass ▲ security
- 30 Oct 26 −14
- Malware scan: pass → unverified ▼ security
- 28 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.
- 26 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 0 to 3. That category is still filling its 30-day observation window: 0 days of observed history at the previous scan, 1 at this one. The score rises as the window fills, whether or not the server changes.
- 25 Oct 26 65
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 5 Nov 2026 · Analysed pypi/ctxfw@4.1.1
Provenance No attestation
The registry publishes no build provenance for this version, so there is nothing to verify.
| Result | No attestation |
|---|---|
| Ecosystem | pypi |
| Reason | No attestation published |
Background: How many MCP packages publish verified provenance →
Install scripts 1 script
| Hook | Tier | Command |
|---|---|---|
| build_backend | Known build tool | hatchling.build |
Background: Why install scripts are a supply-chain risk →
Dependencies 11 packages
| Packages resolved | 11 |
|---|---|
| Stale | 1 |
| Tree resolution | Complete |
Background: SBOMs and build attestations, explained →
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
evaluate_patch ~332
Verify a unified git diff patch (`diff_text`) against SWE-Gate architectural constraints (`max_cyclomatic_delta`, `forbid_type_ignores`, `disallowed_import_modules`) and functional test results (`tests_passed`, `tests_failed`, `functional_verdict`) before allowing merge. Appends immutable audit records (`EVL-...`) in SweGateStore and seals cryptographic blocks in TraceKitStore; use `query_audit_ledger` to retrieve or verify persisted records.
| Name | Type | Req | Description |
|---|---|---|---|
| author_kind | string | – | Patch author kind: 'AGENT' or 'HUMAN' |
| commit_sha | string | – | 40-character lowercase hex commit SHA |
| diff_size_bytes | integer | – | Exact UTF-8 byte length of diff_text |
| diff_text | string | yes | Unified diff text of the candidate patch |
| disallowed_import_modules | array | – | List of banned module names that the patch must not import |
| forbid_type_ignores | boolean | – | Whether introducing '# type: ignore' is forbidden |
| functional_verdict | string | – | Functional test suite verdict: 'PASSED' or 'FAILED' |
| max_cyclomatic_delta | integer | – | Maximum allowed cyclomatic complexity delta |
| pr_id | integer | – | Pull request identifier (>= 1) |
| repo_id | string | – | Optional repository identifier (REPO-...) |
| repo_name | string | – | Repository name (e.g. 'heuristico/ctxfw') |
| tests_failed | integer | – | Count of failing functional tests |
| tests_passed | integer | – | Count of passing functional tests |
| Name | Type | Req | Description |
|---|---|---|---|
| content | array | yes | JSON-serialized SWE-Gate verification report or rejection message |
| isError | boolean | yes | True if the patch was rejected by SWE-Gate or failed validation |
No examples provided.
evaluate_spec_axioms ~102
Evaluate an architectural specification brief (`brief_text`) against formal determinism rules, negative invariant floors ('never'/'shall never'), and the Axiom Completeness Index (ACI 1.0000). Use this during intake or planning phases before writing code. For verifying unified git diff patches, use `evaluate_patch` instead. Pure read-only analytical evaluation with no side effects.
| Name | Type | Req | Description |
|---|---|---|---|
| brief_text | string | yes | Markdown content of the architectural intake brief to evaluate |
| Name | Type | Req | Description |
|---|---|---|---|
| content | array | yes | JSON-serialized architectural determinism verification report |
| isError | boolean | yes | True if brief specification evaluation encountered an unhandled error |
No examples provided.
prune_file ~190
Extract semantic interfaces, types, pydantic models, sanitized raises, and signatures from a source file (`path`) at a given pruning `depth` ('full', 'interface', or 'nominal') and `language`, optionally stripping docstrings (`strip_docs`), while replacing procedural bodies with AST stubs. Use this when you only need to inspect contracts or APIs of an individual dependency without ingesting raw implementation code. For multi-module dependency graphs, use `resolve_context_bundle` instead. Does not modify files on disk (pure in-memory AST operation).
| Name | Type | Req | Description |
|---|---|---|---|
| depth | string | – | Pruning depth: 'full', 'interface', or 'nominal' |
| language | string | – | Programming language (python, typescript, javascript, go, java) |
| path | string | yes | Absolute or relative path to the source file |
| strip_docs | boolean | – | Whether to strip docstrings entirely |
| Name | Type | Req | Description |
|---|---|---|---|
| content | array | yes | Semantic interface stubs extracted via in-memory Tree-Sitter AST |
| isError | boolean | yes | True if pruning encountered a fatal parsing or file resolution failure |
No examples provided.
query_audit_ledger ~208
Retrieve persisted SWE-Gate patch evaluation records and violation findings by `evaluation_id` (`EVL-...`), or verify and inspect cryptographic SHA-256 hash-chained audit sessions in TraceKitStore by `session_id` (`SES-...`) with optional block listing (`include_blocks`, `max_blocks`). Use this for forensic inspection and compliance verification after running `evaluate_patch` or context tools. Pure read-only query with zero ledger mutations.
| Name | Type | Req | Description |
|---|---|---|---|
| evaluation_id | string | – | SWE-Gate evaluation identifier (`EVL-<16 lowercase hex chars>`) returned by `evaluate_patch` |
| include_blocks | boolean | – | Whether to include individual hash-chained audit block records when querying `session_id` |
| max_blocks | integer | – | Maximum number of audit blocks to return when `include_blocks` is true (1 to 256) |
| session_id | string | – | TraceKit session identifier (`SES-...`) to verify SHA-256 hash chain integrity and inspect blocks |
| Name | Type | Req | Description |
|---|---|---|---|
| content | array | yes | JSON-serialized audit ledger query and cryptographic chain verification report |
| isError | boolean | yes | True if neither identifier was provided, parameters failed validation, or no matching audit record was found |
No examples provided.
resolve_context_bundle ~183
Calculate topological dependency graph distances (D0 full `target_file`, D1 interface stubs, D2 nominal symbols) within `project_root` and compile a token-pruned Markdown context bundle, with optional reactive degradation via `breaker_state` and `session_id`. Use this as your primary context builder before editing a file in a multi-module project. For inspecting isolated files, use `prune_file` instead. Read-only operation.
| Name | Type | Req | Description |
|---|---|---|---|
| breaker_state | string | – | Optional circuit breaker state (CLOSED, TRIPPED, HALTED) or decision kind |
| project_root | string | – | Root directory of the project. Defaults to target file's directory. |
| session_id | string | – | Session identifier (SES-...) to connect with TokenCast budget tracking |
| target_file | string | yes | Path to the active target file in editing (D0) |
| Name | Type | Req | Description |
|---|---|---|---|
| content | array | yes | Compiled topological Markdown prompt context bundle |
| isError | boolean | yes | True if dependency resolution or file traversal failed |
No examples provided.
How do I install the io.github.heuristicolab/ctxfw MCP server?
io.github.heuristicolab/ctxfw runs locally as a PyPI package, launched with uvx ctxfw mcp. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
pypi · ctxfw
claude mcp add heuristicolab-ctxfw -- uvx ctxfw mcp
What is the io.github.heuristicolab/ctxfw MCP server?
io.github.heuristicolab/ctxfw is an MCP server listed in the public MCP registry as io.github.heuristicolab/ctxfw. Zero-egress AI Agent Firewall: SARA prompt injection defense, AST context pruning & MCP governance. This page covers its PyPI package (ctxfw).
Is the io.github.heuristicolab/ctxfw MCP server safe to use?
io.github.heuristicolab/ctxfw scores 70 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 5 November 2026. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the io.github.heuristicolab/ctxfw MCP server expose?
io.github.heuristicolab/ctxfw exposes 5 tools: prune_file, resolve_context_bundle, evaluate_spec_axioms, evaluate_patch, query_audit_ledger. Their descriptions and schemas cost roughly 1,015 tokens of context every time the server is loaded.
Is the io.github.heuristicolab/ctxfw MCP server still maintained?
io.github.heuristicolab/ctxfw is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What licence is the io.github.heuristicolab/ctxfw MCP server under?
io.github.heuristicolab/ctxfw declares the Apache-2.0 licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.
What did VerifyMCP test on the io.github.heuristicolab/ctxfw MCP server?
VerifyMCP ran 16 checks on io.github.heuristicolab/ctxfw, covering Malware scan, Known CVEs, Install scripts, Dependency health and 12 more. Endpoint Security and Transport & Reachability do not apply to a PyPI package, so they were not tested. The score does not measure everything, and the scoring documentation lists what it leaves out.