AFFIANT
Something is being sworn.
Affiant is a deterministic evidence layer for .NET: field-level provenance, sworn affidavits, and a human review gate between your LLM and your database.
The problem
AI agents now write to systems of record — closing work orders, adjusting inventory, amending employee files. They do it quickly, and they do it unwitnessed. When the record is later found wrong, nothing can tell you which field the model was told and which it invented.
The evidence card
This reviewer UI holds Approve until a human resolves every Empty field. The framework flags; the host decides.
Every field on an affidavit carries a provenance tag — a sworn statement of where the value came from. A value the user gave you and a value the model guessed are never allowed to look the same.
The Empty tag is not an error. It is the framework refusing to pretend. The proposal cannot be approved until a human resolves it.
The live demos
Two host applications built on Affiant run in public: an aircraft-maintenance desk and a small HR department. Ask either agent to change something and the proposal comes back as an Evidence Card — every field wearing its provenance — and waits for you. Nothing is written until you approve it.
Aircraft maintenance — a fleet of ten, its work orders, a parts inventory. The agent runs on the Microsoft Agent Framework.
Show me all AOG aircraftA read tool. A straight answer.Create an AOG work order for the left engine on A7-BCAThe Evidence Card moment. Approve it, reject it, or amend a field first.Guide me through creating a work orderRule 6, live: the agent guides your UI through a registry, never the DOM.A small HR department — an employee directory, leave requests, expense reports. The agent talks to Microsoft.Extensions.AI directly.
Find employee Priya NairA read tool. Its answer is who "her" means for the rest of the conversation.Submit an expense report of 120 dollars for a client lunch for herThe Evidence Card moment. Approve it, reject it, or amend a field first.Request 1 day of sick leave for her tomorrowAffiant.Policies, live: a standing order approves a day of sick leave with no card at all.The card above is an illustration. These two are real.
Meridian runs on Affiant.Core, Affiant.AgentFramework, Affiant.Docket, Affiant.Policies and Affiant.Transport.SignalR. HR Portal runs on Affiant.Core, Affiant.Extensions.AI, Affiant.Docket, Affiant.EntityFramework, Affiant.Policies and Affiant.Transport.SignalR. Both use Gemini 2.5 Flash. The apps themselves are private first-party hosts; everything they run on is Apache-2.0.
The seven normative rules
One system prompt per agent, immutable after initialization.
Framework code never mutates the system prompt at runtime.
Dual-audience tool returns.
Every tool return is readable by both the LLM and the UI.
Write tools never write.
Write-intent tools produce WriteProposal envelopes; the write happens only after Review Gate confirmation.
Filters over prompts for determinism.
Context extraction, task inference, and review gating live in filters — never in prompt text.
Graceful degradation on provider failure.
A primary LLM outage falls back to a secondary or a deterministic degraded mode. It never throws.
data-guide contracts are UI-layer registrations.
The LLM discovers guidable elements through a route registry, never by inspecting the DOM.
Every Affidavit field carries provenance, no exceptions.
If a field’s origin is unknown, tag it Empty. Never omit.
The provenance ladder
Every value is tagged with exactly one source. They descend from what was sworn to what was never established.
Ten packages, one DAG
Abstractions sits at the root. Core builds on it. The eight adapters build on Core — and never reference each other.
Affiant.AbstractionsPrimitive types and framework interfaces. Zero Affiant dependencies — the root of the DAG.
Affiant.CoreConcrete services: the Context Fabric, the Review Gate, telemetry.
Affiant.SemanticKernelThe Semantic Kernel filter pipeline that intercepts tool calls.
Affiant.AgentFrameworkThe Microsoft Agent Framework bridge, over the same neutral pipeline.
Affiant.Extensions.AIThe Microsoft.Extensions.AI bridge — no agent framework required.
Affiant.DocketThe review queue’s backend-neutral half: in-memory store and the expiry sweep.
Affiant.EntityFrameworkEF Core persistence — SQLite/PostgreSQL sessions and durable Docket stores.
Affiant.PoliciesApproval policies deciding what a human must see.
Affiant.Transport.SignalRStreams affidavits and events to the host UI.
Affiant.Testing.ComplianceHarnessProves your provenance is substantive, not merely shaped.
The honest boundary
Affiant intercepts tool calls invoked locally in your host process — including locally-invoked MCP tools. Hosted, server-side tool execution that runs outside your process is beyond its reach, and Affiant does not claim otherwise.