Struct ToolMetadata 

pub struct ToolMetadata {

    pub namespace: String,
    pub risk: ToolRisk,
    pub is_read_only: bool,
    pub is_concurrency_safe: bool,
    pub supports_streaming: bool,
    pub supports_batch: bool,
    pub supports_rollback: bool,
    pub max_output_bytes: Option<usize>,
    pub exposure: ToolExposure,
    pub capabilities: Vec<String>,
    pub verifier: Option<String>,
    pub examples: Vec<Value>,
    pub tags: Vec<String>,
    pub extensions: Option<HashMap<String, Value>>,
}

Rich metadata for a tool definition.

Provides the harness with enough information for routing, policy, UI, concurrency, traces, verifiers, and search — without relying solely on ToolKind for security decisions.

Fields

namespace: String

Semantic namespace for grouping tools (e.g. “file”, “code”, “process”, “mcp”).

risk: ToolRisk

Risk level hint for the harness: how dangerous is this tool by default.

is_read_only: bool

Whether this tool only reads state (never mutates repo, memory, or config).

is_concurrency_safe: bool

Whether this tool is safe to call concurrently with other tools.

supports_streaming: bool

Whether this tool supports streaming output via events.

supports_batch: bool

Whether this tool can process multiple items in a single call.

supports_rollback: bool

Whether this tool supports rollback (undo of its effects).

max_output_bytes: Option<usize>

Maximum output bytes the tool produces before truncation.

exposure: ToolExposure

Visibility/exposure mode for tool registry routing.

capabilities: Vec<String>

Capabilities required or provided by this tool.

verifier: Option<String>

Verifier spec hint: which verifier to run after this tool completes.

examples: Vec<Value>

Example invocations for the model (shown in tool.search results).

tags: Vec<String>

Tags for search and categorization.

extensions: Option<HashMap<String, Value>>

Arbitrary extended metadata (future-proof).

Implementations

impl ToolMetadata

pub fn read_only() -> Self

Creates a default read-only, safe, simple tool.

pub fn reader(namespace: &str, tags: &[&str]) -> Self

Creates a read tool (file reads, searches).

pub fn writer(namespace: &str, tags: &[&str]) -> Self

Creates a write tool (file writes, edits, patches).

pub fn command(namespace: &str, tags: &[&str]) -> Self

Creates a command/execution tool (bash, process).

pub fn deferred(namespace: &str, risk: ToolRisk, tags: &[&str]) -> Self

Creates a tool that should be deferred (not shown by default).

pub fn internal(namespace: &str, tags: &[&str]) -> Self

Creates an internal/hidden tool.

impl ToolMetadata

pub fn is_default(&self) -> bool

Returns true if this metadata is the default (unset) value. Used by ToolExecutor to detect tools that need builtin metadata injection.

pub fn with_exposure(self, exposure: ToolExposure) -> Self

Builder: sets exposure mode.

pub fn with_capability(self, caps: &[&str]) -> Self

Builder: sets capabilities.

pub fn with_max_output(self, bytes: usize) -> Self

Builder: sets max output bytes.

pub fn with_tags(self, tags: &[&str]) -> Self

Builder: adds tags.

Trait Implementations

impl Clone for ToolMetadata

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ToolMetadata

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

Formats the value using the given formatter.

impl Default for ToolMetadata

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ToolMetadata

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for ToolMetadata

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

where __S: Serializer,

Serialize this value into the given Serde serializer.