Trait ToolEnricher 

pub trait ToolEnricher: Send + Sync {
    // Required methods
    fn supported_categories(&self) -> &[ToolCategory];
    fn enrich_schema(&self, tool_name: &str, schema: &mut ToolSchema);
    fn transform_args(&self, tool_name: &str, args: &mut Value);

    // Provided methods
    fn value_model(&self, _tool_name: &str) -> Option<ToolValueModel> { ... }
    fn project_args(
        &self,
        _prev_tool: &str,
        _prev_result: &Value,
        _link: &FollowUpLink,
    ) -> Option<Value> { ... }
    fn rate_limit_host(&self, _tool_name: &str, _args: &Value) -> Option<String> { ... }
}

Trait for plugins that dynamically modify tool schemas and transform arguments.

Enrichers are executed in registration order by the Executor. Each enricher declares which tool categories it supports — only tools from those categories will be enriched and shown in list_tools().

Required Methods

fn supported_categories(&self) -> &[ToolCategory]

Which tool categories this provider/enricher supports. Tools from other categories won’t be shown when this enricher is active.

fn enrich_schema(&self, tool_name: &str, schema: &mut ToolSchema)

Modify the tool schema during tools/list.

fn transform_args(&self, tool_name: &str, args: &mut Value)

Transform arguments before tool execution.

Provided Methods

fn value_model(&self, _tool_name: &str) -> Option<ToolValueModel>

Optional: provider-shipped value model for tool_name. Returned models are merged into AdaptiveConfig.tools at startup so the Paper 3 enrichment planner can read them via effective_tool_value_model.

Default impl returns None — built-in enrichers that do not participate in the planner can ignore the method entirely.

fn project_args( &self, _prev_tool: &str, _prev_result: &Value, _link: &FollowUpLink, ) -> Option<Value>

Build the JSON arguments for a speculatively pre-fetched follow-up call.

Given the tool that just produced prev_result (prev_tool), the follow-up tool’s FollowUpLink (with projection / projection_arg set), the host asks the enricher: “what args should I pass to <follow-up tool>?”

Returns:

• Some(json) — emit one prefetch request per object in the returned array (planner caps at max_parallel_prefetches). Top-level shape is [{ <args1> }, { <args2> }, …].
• None (default) — provider has no opinion; the host falls back to the generic projection in link.projection_arg.

Built-in enrichers should override this for the high-volume follow-up chains identified in paper3_corpus_findings.md (Glob → Read, Grep → Read, WebSearch → WebFetch, …).

fn rate_limit_host(&self, _tool_name: &str, _args: &Value) -> Option<String>

Optional dynamic rate-limit host for tool_name, derived from runtime args. Provider returns the network host the call will hit (e.g. Some("api.github.com")) so the speculative dispatcher can cap concurrent in-flight prefetches per host.

Default: None — host falls back to ToolValueModel::rate_limit_host (the static configuration value), and if that is also None the prefetch is uncapped.

Override this for tools whose target host is per-call — WebFetch (host from url arg), WebSearch against multiple search engines, MCP wrappers around generic HTTP clients.

Implementors