Struct BindingContext 

#[non_exhaustive]
pub struct BindingContext {
    pub agent_id: String,
    pub session_id: Option<Uuid>,
    pub channel: Option<String>,
    pub account_id: Option<String>,
    pub binding_id: Option<String>,
    pub mcp_channel_source: Option<String>,
    pub event_source: Option<EventSourceMeta>,
    pub tenant_id: Option<String>,
    pub language: Option<String>,
}

Phase 82.1 — binding context propagated to tool calls so extensions and MCP servers can route per-(channel, account_id, agent_id) tuple without re-deriving it from each tool call’s payload.

Serialised under _meta.nexo.binding in JSON-RPC tools/call (extensions ignore unknown fields) and as the meta block of MCP call_tool_with_meta.

agent_id is mandatory; the rest are Option because some dispatch paths (delegation receive, heartbeat bootstrap, tests) have no binding match — None is the correct state, not a sentinel string.

mcp_channel_source is populated when the inbound that triggered this turn arrived via a Phase 80.9 MCP channel server (e.g., "slack", "telegram"). Lets a tool distinguish “telegram-binding answered via MCP slack server” from “telegram-binding answered via native Telegram plugin” while still seeing the same (channel, account_id) binding tuple. Matches the goal_turns.source = "channel:slack" audit column shipped with Phase 80.9. Identifies which inbound binding a tool call originated from.

Stamped on every tool call dispatched to a Phase 11 stdio extension or a Phase 12 MCP server (under params._meta.nexo.binding). A microapp reads it to route work to the correct tenant / channel / account.

binding_id is rendered as <channel>:<account_id|"default"> — a stable identifier that survives agents.yaml reloads (does NOT depend on the binding vector index).

mcp_channel_source is populated when the inbound that triggered the call arrived via a Phase 80.9 MCP channel server ("slack", "telegram", etc.), allowing a tool to distinguish “telegram-binding answered via MCP slack server” from “telegram-binding answered via the native Telegram plugin” while still seeing the same (channel, account_id) tuple.

Example

use nexo_tool_meta::BindingContext;

let ctx = BindingContext::agent_only("ana");
assert_eq!(ctx.agent_id, "ana");
assert!(ctx.channel.is_none());

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

agent_id: String

Stable agent identifier (agents.yaml.<id>).

session_id: Option<Uuid>

Active session UUID. None outside an LLM turn (heartbeat bootstrap, delegation receive, tests).

channel: Option<String>

Channel name as declared in InboundBinding.plugin ("whatsapp", "telegram", "email", "web", …). None for contexts without a binding match.

account_id: Option<String>

Account / instance discriminator from InboundBinding.instance. None when the binding declared no instance (single-account default).

binding_id: Option<String>

Stable binding identifier rendered as <channel>:<account_id|"default">. None for bindingless contexts.

mcp_channel_source: Option<String>

Phase 80.9 — MCP channel server name when the inbound arrived via notifications/nexo/channel. None for native-channel inbounds. Examples: "slack", "telegram", "imessage".

event_source: Option<EventSourceMeta>

Phase 82.4 — event-subscriber metadata when the agent’s inbound was synthesised from a NATS event (subject pattern match). None for human-message turns / native-channel inbounds.

tenant_id: Option<String>

Phase 83.8.12 — SaaS tenant (tenant) key. None for agents that predate the multi-tenant model (agents.yaml.<id> without an tenant_id field). Multi-tenant filtering across admin RPC + microapp tools keys on this field. Sits ABOVE account_id, which remains the channel-side discriminator.

language: Option<String>

Phase 81.19.b locale follow-up item 6 — resolved BCP-47 locale for this binding (InboundBinding.language over AgentConfig.language). When present, the SDK’s STT inbound transform handler trims to ISO-639-1 and passes it as a hint to whisper for accented audio. None lets whisper auto-detect.

Implementations

impl BindingContext

pub fn agent_only(agent_id: impl Into<String>) -> BindingContext

Build the minimum context for a path that has no binding (delegation receive, heartbeat bootstrap, tests). Every optional field stays None.

pub fn with_mcp_channel_source( self, source: impl Into<String>, ) -> BindingContext

Builder helper: layer the MCP channel source on an already-built context. Lets the runtime distinguish a telegram-binding answered via MCP-slack from the same binding answered via the native Telegram plugin.

pub fn binding_id(&self) -> Option<&str>

Cheap accessor — returns the stable <channel>:<account_id|"default"> identifier when available. None for bindingless contexts.

Trait Implementations

impl Clone for BindingContext

fn clone(&self) -> BindingContext

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BindingContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for BindingContext

fn deserialize<__D>( __deserializer: __D, ) -> Result<BindingContext, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for BindingContext

fn eq(&self, other: &BindingContext) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for BindingContext

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for BindingContext

impl StructuralPartialEq for BindingContext