diff --git a/.agents/skills/run-eval.md b/.agents/skills/run-eval.md
index 54e18775ef..2e33366b64 100644
--- a/.agents/skills/run-eval.md
+++ b/.agents/skills/run-eval.md
@@ -32,7 +32,7 @@ curl -X POST \
 
 **Key parameters:**
 - `benchmark`: `swebench`, `swebenchmultimodal`, `gaia`, `swtbench`, `commit0`, `multiswebench`
-- `eval_limit`: `1`, `50`, `100`, `200`, `500`
+- `eval_limit`: Any positive integer (e.g., `1`, `10`, `50`, `200`)
 - `model_ids`: See `.github/run-eval/resolve_model_config.py` for available models
 - `benchmarks_branch`: Use feature branch from the benchmarks repo to test benchmark changes before merging
 
diff --git a/.github/workflows/run-eval.yml b/.github/workflows/run-eval.yml
index 62b8d5029c..4f04a63d8d 100644
--- a/.github/workflows/run-eval.yml
+++ b/.github/workflows/run-eval.yml
@@ -32,16 +32,10 @@ on:
                 default: false
                 type: boolean
             eval_limit:
-                description: Number of instances to run
+                description: Number of instances to run (any positive integer)
                 required: false
                 default: '1'
-                type: choice
-                options:
-                    - '1'
-                    - '100'
-                    - '50'
-                    - '200'
-                    - '500'
+                type: string
             model_ids:
                 description: Comma-separated model IDs to evaluate. Must be keys of MODELS in resolve_model_config.py. Defaults to first model in that
                     dict.
@@ -138,6 +132,14 @@ jobs:
               with:
                   python-version: '3.13'
 
+            - name: Validate eval_limit
+              if: github.event_name == 'workflow_dispatch'
+              run: |
+                  if ! [[ "${{ github.event.inputs.eval_limit }}" =~ ^[1-9][0-9]*$ ]]; then
+                    echo "Error: eval_limit must be a positive integer, got: ${{ github.event.inputs.eval_limit }}"
+                    exit 1
+                  fi
+
             - name: Validate SDK reference (semantic version check)
               if: github.event_name == 'workflow_dispatch'
               env: