docs: clarify baseline deployment name must match pricing config key

Add a comment in .env.example and a callout block in QUICKSTART.md
explaining that AZURE_BASELINE_DEPLOYMENT must match a key in the
pricing section of the config file. If a custom deployment name is used
(e.g. gpt-4o-baseline) without a matching pricing entry, baseline costs
are silently recorded as $0.0000 with no warning, making cost comparison
inaccurate.

Discovered while running evaluations against a Quick Deploy setup.
Applies to both Quick Deploy and Custom Deploy modes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: jpsantoscosta

.env.example

@@ -6,6 +6,9 @@ AZURE_MODEL_ROUTER_DEPLOYMENT=model-router
 # Azure OpenAI endpoint (for baseline model)
 AZURE_OPENAI_ENDPOINT=https://your-resource.openai.azure.com
 AZURE_OPENAI_KEY=your-azure-openai-api-key
+# Must match a key in the pricing section of your config file (e.g. gpt-4o, gpt-5).
+# If you use a custom deployment name, add a matching entry to configs/default.yaml
+# under pricing: using your exact deployment name. Otherwise baseline costs show as $0.00.
 AZURE_BASELINE_DEPLOYMENT=gpt-5
 
 # Judge model (defaults to same endpoint as baseline; override to use a different model)

QUICKSTART.md

@@ -139,6 +139,8 @@ copy .env.example .env     # Windows
 ```
 Open `.env` and set the four endpoint URLs and API keys (router, baseline, judge, optional Foundry project). The file is in `.gitignore`, so your secrets won't be committed.
 
+> **Note:** The value you set for `AZURE_BASELINE_DEPLOYMENT` must match a key in the `pricing` section of your config file. If you use a custom deployment name such as `gpt-4o-baseline`, add a matching entry under `pricing:` in `configs/default.yaml` with the same input/output rates. Otherwise baseline costs will show as $0.00 and the cost comparison will be inaccurate. This applies whether you are using Quick Deploy or Custom Deploy.
+
 ### 2. Pick or edit a config
 - `configs/quick_test.yaml` — small, fast (~10 prompts) — good first run.
 - `configs/default.yaml` — full benchmark (100 prompts).