Feature · Evidence

Evidence you can verify without trusting us.

Microfilm’s signed evidence is tamper-evident test evidence: every event your AI coding agent writes is signed with a KMS-backed key (ES256) and chained into a reel, so any record can be verified offline — without trusting Microfilm — and any later change shows.

Every event written to the MCP server is signed with a KMS-backed key and chained into a reel. The chain is tamper-evident — actor, content, and time fixed at the moment of capture — and any record can be verified offline, so the proof holds up the day someone checks it.

Availability · Included on every plan — signing, chaining, and offline verification are core to Microfilm.

What Microfilm is · Microfilm is the evidence engine for teams and agents: a headless MCP server that AI coding agents write signed test evidence to as they work, paired with a web portal where teams search, trace, and share that evidence. Every event is signed with a KMS-backed key and chained, so any record can be verified offline.

MICROFILM Signed record
Signature
Actor
claude-code · agent
Time
2026-05-13 · 16:42 UTC
Algorithm
KMS-backed ES256
Chained to
a3f9…58e91
Verify
Offline · standalone

The problem

A passing log proves almost nothing.

Console output can be edited, re-dated, or quietly dropped. A spreadsheet of pass/fail can be changed by anyone after the fact, with no trace. When the integrity of your test record matters — and in regulated software it always does — "the build was green" doesn’t hold up.

How it works

What this gives you.

01

Signed at the moment of capture

When the agent writes an event, it’s signed with a KMS-backed key (ES256). Actor, content, and time are fixed together — not added later, not editable after the fact.

MICROFILM at capture
sign
Actor
claude-code · agent
Content
fixed
Time
at write
Signed
KMS · ES256
02

Chained into a tamper-evident reel

Each record links to the one before it. If anything in a sealed reel were altered, the chain would break and it would show. The history of what was tested, by whom, and what the result was stays intact.

MICROFILM reel · linked
chain
Record
reel #1417
Prev
a3f9…58e91
Chain
intact
On change
breaks
03

Verifiable offline

A record carries what’s needed to check its signature and its place in the chain without calling back to Microfilm. Whoever you hand it to can confirm it themselves — integrity you can check, not something you take on faith.

MICROFILM offline check
verify
Input
signed record
Network
none
Checks
signature · chain
Result
authentic
04

Built for the frameworks you answer to

Attributable, time-stamped, append-only records are the shape of evidence regulated environments expect — the same properties teams need when they work toward FedRAMP, CMMC, 21 CFR Part 11, or IEC 62304 review.

MICROFILM evidence shape
properties
Attributable
actor fixed
Time-stamped
at capture
Append-only
yes
Built for
FedRAMP · CMMC · Part 11

Where it fits

Where an event becomes a record

Signing turns each event the agent writes through the MCP server into something durable. From there, signed records land in the evidence portal and remain the source of truth the requirements-traceability views are built over.

  1. 01 Write
    MCP server
  2. 02 Sign
    Signed evidence
  3. 03 Store
    Evidence portal
  4. 04 Trace
    Requirements traceability

FAQ

Common questions.

What does it mean that records are "chained"?

Each signed event links to the one before it, forming a reel. Any change to a sealed record breaks the chain and is detectable, which is what makes the evidence tamper-evident rather than merely stored.

What signs the evidence?

A KMS-backed key using ES256. The private key never leaves the key-management service; Microfilm requests a signature for each event, so the signing material isn’t something the application can leak.

What does "verifiable offline" mean?

A record carries the signature and chain information needed to check it independently — anyone you share it with can confirm it’s authentic and unaltered without trusting Microfilm or being online to our service.

Is signed evidence available on the free plan?

Yes. Signing, chaining, and offline verification are core to Microfilm and included on every plan. The shared portal, search, sharing, and traceability views are Team-and-up cloud features.

Keep exploring

Write your first signed record.

Create an account, connect your agent to the MCP server, and write your first signed record.