Struct PruningCache 

pub struct PruningCache { /* private fields */ }

Per-message cache for MCP tool pruning results.

Stores at most one entry keyed on (message_content_hash, tool_list_hash). A cache miss triggers an LLM call; a hit returns the stored result immediately. Negative entries (Failed) prevent retry storms when the pruning LLM is transiently unavailable.

Cache contract

PruningCache returns previously-computed pruning results keyed on (message_content_hash, tool_list_hash).

tool_list_hash includes: server_id, name, description, and input_schema for every tool. Any change to tool metadata (not just the name set) produces a different hash and causes a cache miss.

PruningCache::reset() is additionally called on:

• New user message (top of process_user_message_inner)
• tools/list_changed notification (in check_tool_refresh)
• Manual /mcp add or /mcp remove commands

PruningParams is not part of the cache key. Callers must not change PruningParams within a single user turn; this invariant holds because params are derived from ToolPruningConfig, which is stable within a turn (config changes trigger a full agent rebuild, not a mid-turn param swap).

Designed for single-owner use (&mut on Agent). Not thread-safe.

Implementations

impl PruningCache

pub fn new() -> Self

Create a new, empty cache.

pub fn reset(&mut self)

Clear the cached entry.

Must be called at the start of each user turn and whenever the MCP tool list changes (via notification, /mcp add, or /mcp remove).

Trait Implementations

impl Clone for PruningCache

fn clone(&self) -> PruningCache

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PruningCache

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

Formats the value using the given formatter.

impl Default for PruningCache

fn default() -> PruningCache

Returns the “default value” for a type.