# Interface Evolution Intent

**Document:** `InterfaceEvolutionIntent.md`  
**Version:** 0.1.0  
**Status:** Template / Normative Companion to FLUID API Standards

---

## 1. Purpose

This document defines the evolutionary intent and governance boundary of a FLUID interface.

It is subordinate to the parent repository or service `INTENT.md` and MUST NOT redefine the overall mission of that service.

Its purpose is to answer:

> **How may this interface evolve while remaining faithful to the service it represents?**

The FLUID Daimon MUST treat this document as a constitutional constraint.

---

## 2. Parent Intent

**Parent service/repository:**  
`<name>`

**Parent intent document:**  
`INTENT.md`

**Relevant parent mission excerpt or reference:**  
`<reference>`

---

## 3. Interface Identity

**Interface name:**  
`<name>`

**Interface identifier:**  
`<stable-id>`

**Current operational authority mode:**  
`FLUID-0 | FLUID-1 | FLUID-2 | FLUID-3 | FLUID-4 | FLUID-5 | FLUID-6`

**Protocols / interface styles:**  

- `<REST>`
- `<GraphQL>`
- `<RPC>`
- `<events>`
- `<other>`

---

## 4. Mission

Describe the outcome the interface exists to enable.

The mission SHOULD focus on consumer outcomes rather than protocol details.

### Mission statement

> `<what useful capability does this interface make conveniently and reliably available?>`

### Success looks like

- `<consumer outcome 1>`
- `<consumer outcome 2>`
- `<consumer outcome 3>`

---

## 5. Intended Consumers

Define the consumers the interface is designed to serve.

### Primary consumer cohorts

| Cohort | Description | Importance | Notes |
|---|---|---:|---|
| `<cohort>` | `<description>` | `<high/medium/low>` | `<notes>` |

### Secondary cohorts

| Cohort | Description | Importance | Notes |
|---|---|---:|---|
| `<cohort>` | `<description>` | `<high/medium/low>` | `<notes>` |

### Explicitly unsupported cohorts

- `<unsupported cohort>`
- `<unsupported cohort>`

---

## 6. Capability Domain

Define which capabilities properly belong inside this interface.

### In scope

- `<capability family>`
- `<capability family>`
- `<capability family>`

### Conditionally in scope

Capabilities that MAY be introduced if evidence justifies them:

- `<conditional capability>`
- `<conditional capability>`

### Out of scope

- `<capability>`
- `<capability>`

---

## 7. Responsibility Boundaries

The FLUID interface owns interface and adapter behavior only.

### Responsibilities owned by this interface

- `<representation>`
- `<composition>`
- `<validation>`
- `<routing>`
- `<other>`

### Responsibilities owned by backend systems

| Backend | Responsibility | Boundary |
|---|---|---|
| `<service>` | `<responsibility>` | `<what FLUID may request but not assume>` |

### Explicit non-authority

The Daimon MUST NOT autonomously:

- `<modify backend domain logic>`
- `<change security policy>`
- `<change tenant boundaries>`
- `<other>`

---

## 8. Consumer Expectation Model

Describe the expectations the interface SHOULD cultivate.

### Concepts consumers should naturally understand

- `<concept>`
- `<concept>`

### Interaction patterns considered natural

- `<pattern>`
- `<pattern>`

### Expectations that should be discouraged

- `<misconception>`
- `<misconception>`

This section provides context when interpreting interface pressure.

---

## 9. Optimization Preferences

The Daimon MUST optimize within declared priorities.

### Active optimization regime

`<EXPLORATION | ADOPTION | UTILITY | PERFORMANCE | RELIABILITY | SECURITY | COST | CONSOLIDATION | MIGRATION | CUSTOM>`

### Fitness priorities

| Dimension | Priority | Target / Constraint | Notes |
|---|---:|---|---|
| Client utility | High | `<target>` | |
| Correctness | High | `<target>` | |
| Reliability | High | `<target>` | |
| Availability | `<...>` | `<target>` | |
| Performance | `<...>` | `<target>` | |
| Discoverability | `<...>` | `<target>` | |
| Simplicity | `<...>` | `<target>` | |
| Compatibility | `<...>` | `<target>` | |
| Security | `<...>` | `<target>` | |
| Maintainability | `<...>` | `<target>` | |
| Operational cost | `<...>` | `<target>` | |
| Implementation cost | `<...>` | `<target>` | |
| Resource consumption | `<...>` | `<target>` | |

### Automatic recommendation policy

`<disabled | advisory | enabled-with-approval | enabled-with-bounded-autonomy>`

---

## 10. Complexity Budget

Complexity is a constrained resource.

### Complexity dimensions

| Dimension | Current | Preferred | Maximum | Scoring method |
|---|---:|---:|---:|---|
| Surface area | | | | |
| Concept count | | | | |
| Operation count | | | | |
| Parameter dimensionality | | | | |
| Semantic overlap | | | | |
| Alternative-path count | | | | |
| Dependency count | | | | |
| Backend composition count | | | | |
| Exception count | | | | |
| Active revision count | | | | |
| Cognitive load | | | | |

### Complexity policy

- New capability SHOULD replace or generalize existing capability where reasonable.
- Semantic duplication SHOULD be rejected unless justified.
- Repeated special-case pressure SHOULD trigger abstraction review.
- Candidates exceeding a hard complexity limit MUST NOT be autonomously promoted.
- Complexity-reducing adaptations MAY be prioritized during consolidation regimes.

---

## 11. Compatibility Policy

### Compatibility posture

`<STRICT | VERSIONED | MANAGED_MIGRATION | CUSTOM>`

### Rules

- Published revision semantics MUST NOT change silently.
- Breaking changes REQUIRE a successor revision.
- `<additional policy>`
- `<additional policy>`

### Coexistence expectations

**Default maximum concurrent major revisions:**  
`<number>`

**Default deprecation period:**  
`<duration or policy>`

**Migration assistance required:**  
`<yes/no + details>`

---

## 12. Revision and Experiment Policy

### Revision classes

- stable;
- candidate;
- experiment;
- deprecated;
- retired.

### Allowed concurrent exposure

| Revision class | Production traffic allowed? | Max share | Approval required? |
|---|---|---:|---|
| stable | yes | 100% | no |
| candidate | `<yes/no>` | `<%>` | `<policy>` |
| experiment | `<yes/no>` | `<%>` | `<policy>` |
| deprecated | yes | `<%>` | no |
| retired | no | 0% | n/a |

### Evolution velocity controls

The Daimon SHOULD slow or freeze promotion when:

- `<regression condition>`
- `<reliability threshold>`
- `<security event>`
- `<budget condition>`

The Daimon MAY accelerate experimentation when:

- `<confidence condition>`
- `<success-rate condition>`
- `<available capacity condition>`

---

## 13. Hypothesis Policy

Nontrivial adaptations SHOULD have explicit hypotheses.

### Minimum evidence for hypothesis creation

- `<threshold>`
- `<cohort diversity requirement>`
- `<observation duration>`
- `<manual exception>`

### Required hypothesis fields

- observation;
- explanation;
- proposed adaptation;
- expected outcome;
- measurement;
- success criteria;
- guardrails;
- complexity impact;
- risk;
- expected learning value.

### Competing hypotheses

`<allowed / encouraged / restricted>`

### Reach preference

Describe whether broad explanatory hypotheses should be favored over local fixes.

`<policy>`

---

## 14. Adaptation Authority

Define what the Daimon may do automatically.

| Adaptation class | Observe | Propose | Generate | Experiment | Promote |
|---|---:|---:|---:|---:|---:|
| Presentation | yes | yes | `<yes/no>` | `<yes/no>` | `<yes/no>` |
| Contract | yes | yes | `<yes/no>` | `<yes/no>` | `<yes/no>` |
| Composition | yes | yes | `<yes/no>` | `<yes/no>` | `<yes/no>` |
| Implementation | yes | yes | `<yes/no>` | `<yes/no>` | `<yes/no>` |
| Requirement escalation | yes | yes | yes | n/a | n/a |

### Absolute prohibitions

The Daimon MUST NOT autonomously:

- expand authorization scope;
- weaken tenant isolation;
- bypass deterministic security controls;
- reinterpret legal constraints;
- create backend authority it does not possess;
- `<additional prohibition>`.

---

## 15. Security Requirements

### Authentication

`<requirements>`

### Authorization

`<requirements>`

### Tenant isolation

`<requirements>`

### Data handling

`<requirements>`

### Logging and provenance

`<requirements>`

### AI boundary

AI-generated changes MUST pass deterministic:

- security policy;
- tests;
- authorization validation;
- tenant-boundary checks;
- release controls.

---

## 16. Quality Requirements

| Quality attribute | Requirement | Hard guardrail? |
|---|---|---:|
| Correctness | `<requirement>` | yes |
| Availability | `<requirement>` | `<yes/no>` |
| Reliability | `<requirement>` | `<yes/no>` |
| p95 latency | `<requirement>` | `<yes/no>` |
| Error rate | `<requirement>` | `<yes/no>` |
| Security | `<requirement>` | yes |
| Auditability | `<requirement>` | yes |
| Rollback | `<requirement>` | yes |

---

## 17. Economic Constraints

### Adaptive compute budget

| Budget | Limit |
|---|---:|
| analysis per day | `<value>` |
| hypothesis generation | `<value>` |
| candidate generation | `<value>` |
| concurrent experiments | `<value>` |
| autonomous implementation effort | `<value>` |

### Cost policy

- Adaptive budget exhaustion MUST NOT affect deterministic runtime availability.
- High-cost / low-value hypotheses SHOULD be deferred.
- `<additional rule>`

---

## 18. Backend Capability Escalation

When a candidate requires backend functionality that is unavailable, the Daimon SHOULD issue a structured capability requirement.

### Preferred requirement destination

`<service / queue / repo / protocol>`

### Required response states

- ACCEPTED;
- PLANNED;
- AVAILABLE;
- PARTIALLY_AVAILABLE;
- OUT_OF_SCOPE;
- REJECTED;
- SUPERSEDED.

### Boundary-learning policy

Repeated `OUT_OF_SCOPE` or `REJECTED` responses SHOULD trigger:

`<intent review / neighboring interface proposal / consumer expectation correction / other>`

---

## 19. Audit and Provenance Policy

For every promoted change the system MUST retain enough evidence to reconstruct:

- originating pressure;
- hypothesis;
- candidate;
- verification;
- approval;
- deployment;
- affected cohorts;
- measured outcome;
- final disposition.

### Retention period

`<duration>`

### Immutable evidence store

`<location / technology / policy>`

---

## 20. Review and Amendment

This document SHOULD be versioned.

Changes to this document SHOULD be treated as governance changes rather than ordinary interface changes.

### Amendment authority

`<role / mechanism>`

### Review cadence

`<cadence>`

### Last reviewed

`<date>`

---

## 21. Summary

The FLUID Daimon SHOULD optimize aggressively **inside** this document and remain conservative **at** its boundaries.

The interface may evolve.

Its intent must remain explicit.