HarnessObjectiveModelEnvironmentRunArtifact + Trace

01 / What is a harness?

Everything the model needs to do a job.

A harness is the runtime setup around a model. It defines what the model can see, what it can do, what rules it must follow, and how the result is checked.

CXT

Context

Data the model can read for this job.

matter · repo · papers

CAP

Tools

Actions the model is allowed to request.

search · shell · write

PRO

Workflow

Instructions and steps for how the job should run.

inspect · reason · test

POL

Rules

Allow, deny, or require approval before a tool runs.

allow · deny · approve

VER

Checks

Tests that decide whether the job actually succeeded.

pass · fail · uncertain

Trace

A record of the actions, outputs, and checks from the run.

events · output · checks

02 / Execution

The model asks. Prismoid decides what runs.

The model can propose a tool call. Prismoid checks the rules, runs the tool, records what happened, and verifies the result.

01Objectivewhat you want done

02Loadcontext + rules

03Modelproposes an action

04Policyallow / deny / approve

05Toolruns in the environment

06Checkverify the result

Typical agent

model returns an answer done

Prismoid

output exists + checks pass + trace recorded done

03 / Reuse

Reuse harnesses like packages.

Start from a base harness, add the tools for the job, then add your company rules. Prismoid resolves the final harness before the run starts.

Harness dependencies

acme/litigation

extendsprismoid/research

extendsprismoid/legal-core

extendsacme/security

resolve · validate · merge

ResolvedHarness IR

sha256:9af…91c

Rulesstrictest rule wins
Checksall required checks run
Toolsmerged by name
Workflowconflicts must be explicit

target / harness.yaml

apiVersion: prismoid.dev/v1
kind: Harness

metadata:
  name: acme-litigation

extends:
  - prismoid/research@1.4
  - prismoid/legal-core@2.1
  - acme/security@7.3

context:
  - legal/matter
  - legal/authorities

capabilities:
  - legal/search-cases
  - documents/write

policies:
  - legal/confidentiality
  - acme/human-approval

verifiers:
  - legal/citation-exists
  - legal/source-support

planned interface prismoid build ./harness.yaml

04 / Harness examples

Same runtime. Different jobs.

The Rust kernel stays the same. Only the harness changes: different context, tools, rules, and checks for each job.

</>engineering/software

Coding harness

Give the model repo context, filesystem and shell tools, and checks that run the build and test suite.

inspectedittestverify

Checkscompile + tests + diff

§legal/research

Legal harness

Give the model case and document search, matter context, citation checks, and approval rules for sensitive actions.

authorityreasoncitecheck

Checkscitation exists + source supports claim

Δscience/research

Scientific harness

Give the model papers, datasets, Python tools, source checks, and numeric/unit validation.

hypothesisevidenceanalyzereplicate

Checkssources + numbers + units

Core rule: the Prismoid kernel contains no coding, legal, or science-specific logic.

05 / Verify the result

Don’t trust “done.” Check it.

A run should leave something you can inspect: the output, the checks that passed or failed, and a trace of what happened.

Artifact — the file, patch, report, or other output.

Checks — tests that confirm the result.

Evidence — sources or results behind the checks.

Trace — the ordered event log for the run.

06 / Architecture

Small core. Everything else is an adapter.

The Rust kernel owns run state, events, artifacts, and verification. Models, MCP, storage, WASI components, and domain code stay outside it.

Domain

codinglegalsciencecompany/private

Components

contexttoolsworkflowruleschecks

Harness

resolvercompilercompositionHarness IR

Kernel

state machineeventsartifactsevidence

Adapters

modelsMCPWASIstorageenvironments

No Agent object in v0.1Start with harness + objective + model + environment.

Tools are explicitA model can only request tools listed by the harness.

Config is resolved firstThe runtime executes normalized Harness IR.

Model vendors are adaptersThe kernel does not depend on OpenAI, Anthropic, or others.

Portable componentsThe target plugin boundary is WIT/WASI, not a Rust ABI.

Checks gate completionThe model cannot mark its own work as successful.

07 / Developer first

Start with one binary.

Prismoid is local-first. Run the CLI on your laptop or in CI. Add SQLite, OCI packages, WASI components, a daemon, and remote execution later without changing the harness format.

prismoid

$ prismoid validate harness.yaml
✓ manifest valid

$ prismoid inspect harness.yaml
✓ Harness IR compiled
  digest blake3:9af…91c

$ prismoid run harness.yaml \
    --objective "Research the issue"

✓ context loaded
✓ rules checked
✓ output produced
✓ 3/3 checks passed

completed · output + trace