> ## Documentation Index
> Fetch the complete documentation index at: https://docs.twirx.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Independent C verifier

> A small portable verifier for canonical observation artifacts and CAS evidence.

The C verifier exists to provide an implementation independent from the Go control path.

It verifies:

* fixed field count and order;
* deterministic CBOR integer forms;
* bounded text and byte strings;
* observation version;
* method and status constraints;
* absence of trailing bytes;
* body path, size, and SHA-256 digest.

It does not:

* access the network;
* resolve DNS;
* parse arbitrary HTML or JSON;
* load plugins;
* interpret ontology mappings;
* hold credentials;
* write canonical state.

Build assurance includes GCC, Clang, AddressSanitizer, UndefinedBehaviorSanitizer, and corrupted-evidence tests.

`conformance/observation/vectors.json` is the shared Go/C corpus. The C test
harness materializes each vector, verifies its declared acceptance class, and
then replaces valid evidence to prove digest rejection. A separate libFuzzer
target mutates the bounded envelope parser without filesystem or network
access; sanitizer findings fail the Gate 1 suite.

The verifier is intentionally narrow. C supplies portability and independent assurance without becoming the exposed hostile-web runtime.