docs: add LIMITATIONS.md, and fix the SPONSORS page 404 while registering it

.github/workflows/docs.yml

@@ -16,6 +16,8 @@ on:
       - "overrides/**"
       - "index.md"
       - "CODE_OF_CONDUCT.md"
+      - "LIMITATIONS.md"
+      - "SPONSORS.md"
   workflow_dispatch:
 
 permissions:
@@ -59,7 +61,7 @@ jobs:
           # measurement/REPORT.md is in the nav as Self-verification.
           if [ -d measurement ]; then cp -r measurement $BUILD/measurement; fi
 
-          for fname in index.md CHANGELOG.md CONTRIBUTING.md CODE_OF_CONDUCT.md PRIVACY.md CNAME; do
+          for fname in index.md CHANGELOG.md CONTRIBUTING.md CODE_OF_CONDUCT.md LIMITATIONS.md SPONSORS.md PRIVACY.md CNAME; do
             if [ -f "$fname" ]; then cp "$fname" "$BUILD/$fname"; fi
           done
 

LIMITATIONS.md

@@ -0,0 +1,67 @@
+# Known Limitations
+
+What this suite does **not** establish. A conformance report is only useful if the reader knows
+what it was never checking, so this is the companion to the report rather than a footnote to it.
+
+## What a pass means
+
+**A pass describes the record, not the agent.**
+Conformance means the record is well formed, internally consistent, and carries what its level
+requires. It says nothing about whether the agent behaved well, whether the policy it ran under
+was a sensible policy, or whether the run should have been allowed. A record of a bad run passes
+exactly as cleanly as a record of a good one.
+
+**The suite is one implementation, not the definition.**
+[trace-spec](https://github.com/agentrust-io/trace-spec) is normative. Where this suite and the
+specification disagree, the specification is what other implementations were written against and
+the disagreement is a bug worth reporting here.
+
+## Where the checks stop
+
+**`TR-RTE` checks the shape of the attestation fields, not the attestation.**
+It validates that `runtime.platform` is a recognised value, that `runtime.measurement` is a well
+formed digest, and that the RIM URI parses. It does not obtain a quote, and it does not verify one
+against AMD, Intel or a TPM manufacturer root. A record can satisfy `TR-RTE` at Level 1 carrying a
+syntactically perfect measurement that no hardware ever produced. Verifying the quote against the
+silicon vendor is the relying party's job, and `cmcp_verify` is where that happens.
+
+**`TR-ANC-002` proves inclusion relative to the receipt you hand it.**
+It replays the audit path against the Merkle root carried in that receipt. It does not fetch the
+`transparency` URI, and it does not establish that the root is one a public log actually
+published. A self-consistent receipt over a tree the submitter built themselves will pass. What
+the check rules out is a record that has been modified since anchoring, or that was never in the
+tree the receipt commits to. Establishing that the tree is real is a separate step and is not in
+scope here.
+
+`TR-ANC-001` is explicit that it checks the pointer rather than the anchor. Supplying no receipt
+fails `TR-ANC-002`, so Level 2 cannot be reached on a well formed URI alone.
+
+## Statuses that are easy to misread
+
+**`UNVERIFIED` is about reachability, not correctness.**
+It means the check could not be run against the evidence the record cites. The evidence may be
+perfectly good and simply out of reach. It is deliberately held apart from a skip so that it can
+never be read as a benign omission.
+
+Whether an unverified finding fails a run is decided per code, in
+`src/trace_tests/modules/unverified.py`, not by one blanket rule. `TR-POL-003` is tolerated until
+Level 2; anything the table does not name fails from Level 1, so a newly added code fails closed
+rather than turning a run quietly permissive.
+
+**A `TR-ENV` profile failure is a version mismatch before it is a defect.**
+Suite 0.4.0 and later require v0.2 records. Run against a v0.1 record, the profile sentinel
+produces a confident failure on a record that is fine. Check the suite and record versions before
+believing that result.
+
+**Results are perishable.**
+`TR-ENV` validates `iat`, so a record that passes today can fail later with nothing about the
+record having changed. A report is a statement about a moment, and it needs its timestamp to be
+read correctly.
+
+## Who is asserting what
+
+**Nothing here is independently assessed.**
+A report is produced by whoever ran the suite, on evidence they supplied. There is no third-party
+assessor and no certification programme behind it. This is why the generated report tells a reader
+who does not trust the sender to go and check the record themselves rather than trusting the
+summary.

README.md

@@ -87,6 +87,7 @@ and CI.
 | 🗂 Test schemas | [schemas/](schemas/) |
 | 💬 Discussions | [GitHub Discussions](https://github.com/orgs/agentrust-io/discussions) |
 | 📋 Changelog | [CHANGELOG.md](CHANGELOG.md) |
+| ⚠️ Known limitations | [LIMITATIONS.md](LIMITATIONS.md) |
 
 ## Contributing
 

mkdocs.yml

@@ -175,6 +175,7 @@ nav:
       - Contributing: CONTRIBUTING.md
       - Code of Conduct: CODE_OF_CONDUCT.md
       - Privacy: PRIVACY.md
+      - Known limitations: LIMITATIONS.md
 
 extra_javascript:
   - https://agentrust-io.com/supernav.js