Constants in your coding agent · v1

Test a public preview, inspect findings and evidence, fix your application, and verify the fix without leaving Codex or Claude Code. Constants executes tests and records evidence. Your coding agent interprets the reports and edits your code using its existing permissions.

• Connect Codex or Claude Code
• Test a change
• Read reports and evidence
• Verify fixes
• User studies
• Troubleshooting

The public-preview workflow works through direct MCP. An optional plugin adds three workflow skills.

Tools: get_account, list_workspaces, list_test_files, list_runs, start_test, get_run, get_report, verify_run, cancel_run, create_share_link, revoke_share_link.

User studies have their own MCP server, https://mcp.reports.constants.io/studies/mcp, for running studies with real participants: see User studies.

New MCP explorations and verifications spend the selected workspace’s credits, like web and REST/CLI simulations: 40 credits per session minute, rounded up, per simulation. Each simulation reserves up to 800 credits (20 minutes), limited to the whole minutes the available balance covers, and releases unused credits when it ends. get_account reports the workspace allowance and creditsPerMinute: 40; starts report credits.held and completed runs report credits.charged. Historical exempt runs and same-key retries retain their original accounting. Reading reports and evidence is free.

New reports created through a coding agent are private: current members of the test's workspace can open them after signing in. When you ask, your coding agent can share a report with create_share_link, or you can set General access to Anyone with the link on the report page while signed in. Your reports are listed in My Reports. A shared report keeps its usual URL: anyone with it, including links to a tab or moment in the report, can view the report and recording without signing in until sharing is turned off. Reports that were already public stay public. Viewing a report never authorizes a new test.