feat: rename the default harness to bash

[mikasenghaas]

Summary

• Rename the built-in default harness to bash — the tool-enabled bash (+ edit/search) agent.
• Move verifiers/v1/harnesses/default/ → verifiers/v1/harnesses/bash/ and rename DefaultHarness/DefaultHarnessConfig → BashHarness/BashHarnessConfig.
• Change the fallback harness id (used when no harness is specified) from default to bash: HarnessConfig.id, EnvConfig.harness, and loaders.default_harness_id.
• Rename the default pytest marker to bash.
• Update docs, skills, and example configs (configs/harbor.toml, configs/gsm8k.toml, docs/v1/*).

Breaking

The harness id default no longer exists — no alias is kept.

• Configs: any harness = { id = "default", ... } (or [harness]\nid = "default") must change to id = "bash".
• Fallback: configs that relied on the implicit fallback keep working — the fallback is now bash and resolves to the same harness.
• Python API: import BashHarness / BashHarnessConfig from verifiers.v1.harnesses instead of DefaultHarness / DefaultHarnessConfig.
• Tests: -m default → -m bash.

Downstream prime-rl example configs reference id = "default" and need a companion update (examples/{glm5_pd_disag,intellect-3.1,minimax_m2.5_swe,qwen30b_swe}/rl.toml).

Verification

• harness_class("bash") is BashHarness, default_harness_id("") == "bash", HarnessConfig().id == "bash", EnvConfig().harness.id == "bash", load_harness(HarnessConfig(id="bash")) → BashHarness — all pass.
• uv run pytest tests/v1 --collect-only -m bash collects the 8 bash-harness e2e cases; uv run pytest --markers lists @pytest.mark.bash (no default).

🤖 Generated with Claude Code

---

Note

Medium Risk
Breaking API and config change for any explicit harness.id = "default" or DefaultHarness imports; implicit defaults remain equivalent but downstream repos (e.g. prime-rl examples) need coordinated updates.

Overview
Breaking rename: the tool-enabled built-in harness id changes from default to bash. The implementation moves from verifiers/v1/harnesses/default/ to verifiers/v1/harnesses/bash/ with DefaultHarness / DefaultHarnessConfig renamed to BashHarness / BashHarnessConfig; public exports in verifiers.v1.harnesses follow suit.

Defaults and resolution: implicit harness selection now uses bash everywhere it previously used default — HarnessConfig.id, EnvConfig.harness, and loaders.default_harness_id(). Configs that omit harness.id still get the same agent behavior under the new id.

Tooling and docs: example TOMLs (harbor, gsm8k), v1 docs/skills, init scaffold text, and the v1 e2e pytest marker switch from default to bash (-m bash). The default harness id is not kept as an alias; callers must use id = "bash" and import BashHarness types.

^{Reviewed by Cursor Bugbot for commit 320e4ed. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Rename the default harness to bash across configs, code, and docs

• Renames DefaultHarness/DefaultHarnessConfig to BashHarness/BashHarnessConfig and moves the implementation from verifiers/v1/harnesses/default/ to verifiers/v1/harnesses/bash/.
• Changes the default id in HarnessConfig and EnvConfig from "default" to "bash", and updates default_harness_id() in loaders.py to return "bash" when no taskset harness is found.
• Updates all TOML configs, docs, skill references, CLI templates, and test fixtures to use the bash harness id and marker.
• Behavioral Change: any code that resolves a harness by the string "default" will no longer match the built-in harness; callers must use "bash".

^{Macroscope summarized 320e4ed.}

[macroscopeapp]

Approvability

Verdict: Approved

Mechanical rename from 'default' to 'bash' harness throughout the codebase. All changes are naming-only (class renames, string literals, docs, configs) with no behavioral impact.

^{You can customize Macroscope's approvability policy. Learn more.}