Enum HookResult 

pub enum HookResult {
    Continue,
    Block {
        reason: String,
    },
    Inject {
        content: String,
    },
    Confirm {
        message: String,
    },
    Modify {
        input: Value,
    },
    Replace {
        output: String,
    },
}

What an extension handler returns after processing a hook event.

The runtime resolves multiple handlers by precedence:

• Block, Confirm, and Modify stop the handler chain for before_tool_call.
• Inject results are accumulated for before_message.
• Continue is the no-op default — processing continues normally.

Variants

Continue

Allow execution to proceed unchanged.

Block

Prevent the hooked operation. The reason is surfaced to the user.

Fields

reason: String

Inject

Inject context — the extension provides text for the current request. Placement depends on the hook (#297): on_session_start content is appended to the system prompt (session-stable, cache-safe); before_message content is attached to the newest user message on the outgoing request as an ephemeral trailing block positioned AFTER the conversational cache marker (per-turn, uncached tail, cache-neutral).

Fields

content: String

Confirm

Ask the runtime to get explicit user confirmation before proceeding. Only valid on before_tool_call hooks.

Fields

message: String

Modify

Replace the tool input before execution (structured JSON args). Only valid on before_tool_call hooks. The output-side counterpart is HookResult::Replace. The first modifier stops the handler chain.

Fields

input: Value

Replace

Replace the tool output after execution (flat string), before it enters history. Only valid on after_tool_call hooks. The input-side counterpart is HookResult::Modify — distinct name because the payload is an unstructured String, not structured Value. Enables native output transforms (compression, redaction, summarization) by extensions. The first transform stops the handler chain.

Fields

output: String

Trait Implementations

impl Clone for HookResult

fn clone(&self) -> HookResult

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HookResult

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

Formats the value using the given formatter.

impl Default for HookResult

fn default() -> HookResult

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for HookResult

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for HookResult

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for HookResult

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 StructuralPartialEq for HookResult