Module ir 

The canonical, version-agnostic IR.

What this is for

Application code and user handlers see these types. They do not see a revision’s wire types, and they never choose a version at compile time. T08 adds per-revision codecs that lift the wire into this IR and lower it back out, so the same handler serves every revision and the bridge between them is pure data.

The three properties everything here is built around

Superset. Every revision’s types are a subset of these. Fields a newer revision added are Option and absent on older ones, so a 2024-11-05 value and a 2026-07-28 value are both representable, and the difference is visible rather than typed away.

Self-describing requirements. Every value can report what it needs to be expressed through required_features(). Lowering asks that question rather than pattern-matching on a version, so adding a revision does not mean touching every encoder — a new revision turns on the features it defines, and the existing gates do the rest.

Lossless. Unmodelled fields land in an Extensions bag instead of being dropped, and an unparseable value lands as Raw rather than disappearing. The bridge’s lift(v, lower(v, ir)) == ir claim is only meaningful because of this, and it is the property the crate exists for.

The layering

mod features;    // FeatureSet — what a value needs
mod json;        // JsonObject — arbitrary JSON, validated once
mod extensions;  // Extensions  — the passthrough bag
mod content;     // Content     — content blocks
mod message;     // IrMessage   — the envelope
mod tool;        // ToolResult  — and the downgrade fallback

Each file holds one concern, and the dependency direction is downward: content, tool, codec and lower use features, json and extensions, and nothing uses content. message sits above the rest and is the only place they are assembled. codec and lower are public because the adapter layer implements their traits and a bridge reads the reports those traits produce.

Re-exports

pub use loglevel::Level as LogLevel;

pub use loglevel::LevelError as LogLevelError;

pub use lower::DegradeRule;

pub use lower::Loss;

pub use lower::LowerError;

pub use lower::Lowering;

pub use lower::TranslationReport;

pub use lower::TranslationStep;

Modules

loglevel

LogLevel — the severity ladder a notifications/message record carries.

lower

Lowering — making an IR value expressible at a target revision, or refusing.

Structs

Annotations

Annotations, added in 2025-03-26 (PR #185).

AudioContent

The audio block, 2025-03-26 and later.

Downgrade

A change lowering made to make a value expressible.

EmbeddedResource

A resource’s contents, inline.

Extensions

Unmodelled fields, in serde_json::Map order.

FeatureSet

A set of features.

GetPromptResult

What prompts/get answers with.

ImageContent

{"type": "image", "data": "...", "mimeType": "..."}.

IrError

An error result.

IrNotification

A notification. Never has an id, never gets a reply.

IrParams

The parameters of a request or notification.

IrRequest

A request. Expects exactly one result or error.

IrResult

A successful result.

JsonObject

A JSON object, validated on construction.

MethodName

A method name, validated.

PromptMessage

One message of a prompts/get result.

ResourceContents

One entry of a resources/read result’s contents array.

ResourceIcon

An icon for a resource link. 2025-11-25, SEP-973.

ResourceLinkContent

A link to a resource, 2025-06-18 and later (PR #603).

TextContent

{"type": "text", "text": "..."}.

ToolResult

The result of calling a tool.

UnknownContent

A content block whose type this build does not know.

UnknownRole

A role this build does not recognise.

Enums

Content

A content block.

EnvelopeError

An envelope this build could not lift.

ExtensionValue

The value of an unmodelled field.

IrErrorCode

A JSON-RPC error code.

IrMessage

Any message in either direction.

JsonObjectError

Why a string is not a JsonObject.

MethodNameError

Why a method name is not a MethodName.

ResourceBody

A resource’s body.

Role

Who a content block is meant for.

Traits

Codec

Translates between one revision’s wire type and the canonical IR.

Functions

lift_envelope

Lifts one wire envelope into the IR.

lower_envelope

Re-emits an IR message as a wire envelope.