docs(security): say what the scanners cover and what guards the price

CONTRIBUTING.md

@@ -26,6 +26,14 @@ the conversation toward config before anyone writes code.
 If a vendor is nearly compatible and something small blocks it, that is a bug in
 the adapter worth fixing, not a reason for a fourth one.
 
+**A new adapter config must not commit the vendor's published rates.** Name the
+tariff page and leave the figures to the operator's own `--pricing` table. Some
+vendors' terms make their pricing confidential and override the usual
+public-knowledge exclusion, so copying a rate out of a public page into a file
+this project publishes is a disclosure by this project. Secret scanning will not
+catch it, because a price is not a credential format; see SECURITY.md and the
+test named there.
+
 ## The rule about figures
 
 **No figure may be rendered without its n and its null.**

SECURITY.md

@@ -22,6 +22,40 @@ Please do not open a public issue for a security problem.
   it does not change the answer.
 - `.env` is gitignored. `.env.example` is the template and holds no values.
 
+## What the automated controls cover, and what they do not
+
+This repository has secret scanning and push protection enabled. Both work by
+recognising **credential formats**: a token that looks like a token gets caught,
+and push protection rejects the commit before it lands. That is the right
+control for a leaked key and it is the reason a key has never reached a commit
+here.
+
+It is worth being precise about what that leaves.
+
+The closest thing to a disclosure this project has actually had was not a
+credential. It was a **vendor's price**, quoted from their documentation into a
+shipped config file, under a customer agreement that makes pricing information
+confidential and expressly overrides the usual public-knowledge exclusion. No
+scanner recognises a price. `0.042` is a float. Push protection would have
+passed it through without a murmur, and did, until it was caught by reading.
+
+Contractual confidentiality is not a pattern-matching problem, so it does not
+get a pattern-matching control. What guards it here is design and a test:
+
+- **Design.** plumbline ships no pricing figures for a vendor whose terms treat
+  them as confidential. The shipped entry names the tariff page and prices
+  nothing, and the operator supplies the numbers themselves through
+  `--pricing`, in their own working copy. Reading a published page and writing
+  the number down is the operator's act, not this project's.
+- **A test.** `tests/test_cost_and_latency.py::test_no_shipped_entry_states_a_figure_for_the_confidential_vendor`
+  asserts that no shipped entry for that vendor carries a numeric price, in
+  either a price field or its source string. It fails if a number is put back
+  in a price field, and it fails if a price is quoted in the prose around one.
+  Both paths were verified by injecting a figure and watching it go red.
+
+If you are reviewing a change that touches pricing, that test is the control.
+Do not assume a green secret-scanning badge says anything about it.
+
 ## Run artifacts contain your data
 
 This is the part worth pausing on.

docs/PLAN.md

@@ -109,6 +109,21 @@ Settled during the build. Reopen one only with a reason, not from scratch.
   about the system under test. A decline is recorded as a refusal with its
   category and counted. The tradeoff is stated at the call site in
   `adapters/generative.py`; it is not an oversight.
+- CodeQL default setup is kept for its **`actions`** coverage, not its Python
+  coverage. Workflow script injection is a real class of bug and `ci.yml` is
+  where it would hide. The Python queries are expected to be low yield on this
+  codebase: it is a CLI with no attacker in its threat model, run by an
+  operator on their own data with their own key. The first full scan produced
+  exactly one alert, a false positive on a test assertion
+  (`py/incomplete-url-substring-sanitization`, a substring check that makes no
+  security decision), dismissed with that reasoning. **Turn it off if a second
+  false positive appears on ordinary work**; at that point it is costing review
+  attention it is not repaying. It is a setting, not a workflow file, so
+  disabling it is one API call and leaves no trace in the tree.
+- Secret scanning and push protection guard credential formats and nothing
+  else. The disclosure risk this project actually has is contractual, and the
+  control for it is the `--pricing` design plus a test. SECURITY.md says so in
+  full, because a green scanning badge invites the wrong assumption.
 
 ## Live validation