rig/tool/
mod.rs

1//! Module defining tool related structs and traits.
2//!
3//! The [Tool] trait defines a simple interface for creating tools that can be used
4//! by [Agents](crate::agent::Agent).
5//!
6//! The [ToolEmbedding] trait extends the [Tool] trait to allow for tools that can be
7//! stored in a vector store and RAGged.
8//!
9//! The [ToolSet] struct is a collection of tools that can be used by an [Agent](crate::agent::Agent)
10//! and optionally RAGged.
11
12pub mod server;
13use std::collections::HashMap;
14
15use futures::Future;
16use serde::{Deserialize, Serialize};
17
18use crate::{
19    completion::{self, ToolDefinition},
20    embeddings::{embed::EmbedError, tool::ToolSchema},
21    wasm_compat::{WasmBoxedFuture, WasmCompatSend, WasmCompatSync},
22};
23
24#[derive(Debug, thiserror::Error)]
25pub enum ToolError {
26    #[cfg(not(target_family = "wasm"))]
27    /// Error returned by the tool
28    #[error("ToolCallError: {0}")]
29    ToolCallError(#[from] Box<dyn std::error::Error + Send + Sync>),
30
31    #[cfg(target_family = "wasm")]
32    /// Error returned by the tool
33    #[error("ToolCallError: {0}")]
34    ToolCallError(#[from] Box<dyn std::error::Error>),
35
36    #[error("JsonError: {0}")]
37    JsonError(#[from] serde_json::Error),
38}
39
40/// Trait that represents a simple LLM tool
41///
42/// # Example
43/// ```
44/// use rig::{
45///     completion::ToolDefinition,
46///     tool::{ToolSet, Tool},
47/// };
48///
49/// #[derive(serde::Deserialize)]
50/// struct AddArgs {
51///     x: i32,
52///     y: i32,
53/// }
54///
55/// #[derive(Debug, thiserror::Error)]
56/// #[error("Math error")]
57/// struct MathError;
58///
59/// #[derive(serde::Deserialize, serde::Serialize)]
60/// struct Adder;
61///
62/// impl Tool for Adder {
63///     const NAME: &'static str = "add";
64///
65///     type Error = MathError;
66///     type Args = AddArgs;
67///     type Output = i32;
68///
69///     async fn definition(&self, _prompt: String) -> ToolDefinition {
70///         ToolDefinition {
71///             name: "add".to_string(),
72///             description: "Add x and y together".to_string(),
73///             parameters: serde_json::json!({
74///                 "type": "object",
75///                 "properties": {
76///                     "x": {
77///                         "type": "number",
78///                         "description": "The first number to add"
79///                     },
80///                     "y": {
81///                         "type": "number",
82///                         "description": "The second number to add"
83///                     }
84///                 }
85///             })
86///         }
87///     }
88///
89///     async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
90///         let result = args.x + args.y;
91///         Ok(result)
92///     }
93/// }
94/// ```
95pub trait Tool: Sized + WasmCompatSend + WasmCompatSync {
96    /// The name of the tool. This name should be unique.
97    const NAME: &'static str;
98
99    /// The error type of the tool.
100    type Error: std::error::Error + WasmCompatSend + WasmCompatSync + 'static;
101    /// The arguments type of the tool.
102    type Args: for<'a> Deserialize<'a> + WasmCompatSend + WasmCompatSync;
103    /// The output type of the tool.
104    type Output: Serialize;
105
106    /// A method returning the name of the tool.
107    fn name(&self) -> String {
108        Self::NAME.to_string()
109    }
110
111    /// A method returning the tool definition. The user prompt can be used to
112    /// tailor the definition to the specific use case.
113    fn definition(
114        &self,
115        _prompt: String,
116    ) -> impl Future<Output = ToolDefinition> + WasmCompatSend + WasmCompatSync;
117
118    /// The tool execution method.
119    /// Both the arguments and return value are a String since these values are meant to
120    /// be the output and input of LLM models (respectively)
121    fn call(
122        &self,
123        args: Self::Args,
124    ) -> impl Future<Output = Result<Self::Output, Self::Error>> + WasmCompatSend;
125}
126
127/// Trait that represents an LLM tool that can be stored in a vector store and RAGged
128pub trait ToolEmbedding: Tool {
129    type InitError: std::error::Error + WasmCompatSend + WasmCompatSync + 'static;
130
131    /// Type of the tool' context. This context will be saved and loaded from the
132    /// vector store when ragging the tool.
133    /// This context can be used to store the tool's static configuration and local
134    /// context.
135    type Context: for<'a> Deserialize<'a> + Serialize;
136
137    /// Type of the tool's state. This state will be passed to the tool when initializing it.
138    /// This state can be used to pass runtime arguments to the tool such as clients,
139    /// API keys and other configuration.
140    type State: WasmCompatSend;
141
142    /// A method returning the documents that will be used as embeddings for the tool.
143    /// This allows for a tool to be retrieved from multiple embedding "directions".
144    /// If the tool will not be RAGged, this method should return an empty vector.
145    fn embedding_docs(&self) -> Vec<String>;
146
147    /// A method returning the context of the tool.
148    fn context(&self) -> Self::Context;
149
150    /// A method to initialize the tool from the context, and a state.
151    fn init(state: Self::State, context: Self::Context) -> Result<Self, Self::InitError>;
152}
153
154/// Wrapper trait to allow for dynamic dispatch of simple tools
155pub trait ToolDyn: WasmCompatSend + WasmCompatSync {
156    fn name(&self) -> String;
157
158    fn definition<'a>(&'a self, prompt: String) -> WasmBoxedFuture<'a, ToolDefinition>;
159
160    fn call<'a>(&'a self, args: String) -> WasmBoxedFuture<'a, Result<String, ToolError>>;
161}
162
163impl<T: Tool> ToolDyn for T {
164    fn name(&self) -> String {
165        self.name()
166    }
167
168    fn definition<'a>(&'a self, prompt: String) -> WasmBoxedFuture<'a, ToolDefinition> {
169        Box::pin(<Self as Tool>::definition(self, prompt))
170    }
171
172    fn call<'a>(&'a self, args: String) -> WasmBoxedFuture<'a, Result<String, ToolError>> {
173        Box::pin(async move {
174            match serde_json::from_str(&args) {
175                Ok(args) => <Self as Tool>::call(self, args)
176                    .await
177                    .map_err(|e| ToolError::ToolCallError(Box::new(e)))
178                    .and_then(|output| {
179                        serde_json::to_string(&output).map_err(ToolError::JsonError)
180                    }),
181                Err(e) => Err(ToolError::JsonError(e)),
182            }
183        })
184    }
185}
186
187#[cfg(feature = "rmcp")]
188#[cfg_attr(docsrs, doc(cfg(feature = "rmcp")))]
189pub mod rmcp {
190    use crate::completion::ToolDefinition;
191    use crate::tool::ToolDyn;
192    use crate::tool::ToolError;
193    use crate::wasm_compat::WasmBoxedFuture;
194    use rmcp::model::RawContent;
195    use std::borrow::Cow;
196
197    pub struct McpTool {
198        definition: rmcp::model::Tool,
199        client: rmcp::service::ServerSink,
200    }
201
202    impl McpTool {
203        pub fn from_mcp_server(
204            definition: rmcp::model::Tool,
205            client: rmcp::service::ServerSink,
206        ) -> Self {
207            Self { definition, client }
208        }
209    }
210
211    impl From<&rmcp::model::Tool> for ToolDefinition {
212        fn from(val: &rmcp::model::Tool) -> Self {
213            Self {
214                name: val.name.to_string(),
215                description: val.description.clone().unwrap_or(Cow::from("")).to_string(),
216                parameters: val.schema_as_json_value(),
217            }
218        }
219    }
220
221    impl From<rmcp::model::Tool> for ToolDefinition {
222        fn from(val: rmcp::model::Tool) -> Self {
223            Self {
224                name: val.name.to_string(),
225                description: val.description.clone().unwrap_or(Cow::from("")).to_string(),
226                parameters: val.schema_as_json_value(),
227            }
228        }
229    }
230
231    #[derive(Debug, thiserror::Error)]
232    #[error("MCP tool error: {0}")]
233    pub struct McpToolError(String);
234
235    impl From<McpToolError> for ToolError {
236        fn from(e: McpToolError) -> Self {
237            ToolError::ToolCallError(Box::new(e))
238        }
239    }
240
241    impl ToolDyn for McpTool {
242        fn name(&self) -> String {
243            self.definition.name.to_string()
244        }
245
246        fn definition(&self, _prompt: String) -> WasmBoxedFuture<'_, ToolDefinition> {
247            Box::pin(async move {
248                ToolDefinition {
249                    name: self.definition.name.to_string(),
250                    description: self
251                        .definition
252                        .description
253                        .clone()
254                        .unwrap_or(Cow::from(""))
255                        .to_string(),
256                    parameters: serde_json::to_value(&self.definition.input_schema)
257                        .unwrap_or_default(),
258                }
259            })
260        }
261
262        fn call(&self, args: String) -> WasmBoxedFuture<'_, Result<String, ToolError>> {
263            let name = self.definition.name.clone();
264            let arguments = serde_json::from_str(&args).unwrap_or_default();
265
266            Box::pin(async move {
267                let result = self
268                    .client
269                    .call_tool(rmcp::model::CallToolRequestParam { name, arguments })
270                    .await
271                    .map_err(|e| McpToolError(format!("Tool returned an error: {e}")))?;
272
273                if let Some(true) = result.is_error {
274                    let error_msg = result
275                        .content
276                        .into_iter()
277                        .map(|x| x.raw.as_text().map(|y| y.to_owned()))
278                        .map(|x| x.map(|x| x.clone().text))
279                        .collect::<Option<Vec<String>>>();
280
281                    let error_message = error_msg.map(|x| x.join("\n"));
282                    if let Some(error_message) = error_message {
283                        return Err(McpToolError(error_message).into());
284                    } else {
285                        return Err(McpToolError("No message returned".to_string()).into());
286                    }
287                };
288
289                Ok(result
290                    .content
291                    .into_iter()
292                    .map(|c| match c.raw {
293                        rmcp::model::RawContent::Text(raw) => raw.text,
294                        rmcp::model::RawContent::Image(raw) => {
295                            format!("data:{};base64,{}", raw.mime_type, raw.data)
296                        }
297                        rmcp::model::RawContent::Resource(raw) => match raw.resource {
298                            rmcp::model::ResourceContents::TextResourceContents {
299                                uri,
300                                mime_type,
301                                text,
302                                ..
303                            } => {
304                                format!(
305                                    "{mime_type}{uri}:{text}",
306                                    mime_type = mime_type
307                                        .map(|m| format!("data:{m};"))
308                                        .unwrap_or_default(),
309                                )
310                            }
311                            rmcp::model::ResourceContents::BlobResourceContents {
312                                uri,
313                                mime_type,
314                                blob,
315                                ..
316                            } => format!(
317                                "{mime_type}{uri}:{blob}",
318                                mime_type = mime_type
319                                    .map(|m| format!("data:{m};"))
320                                    .unwrap_or_default(),
321                            ),
322                        },
323                        RawContent::Audio(_) => {
324                            unimplemented!("Support for audio results from an MCP tool is currently unimplemented. Come back later!")
325                        }
326                        thing => {
327                            unimplemented!("Unsupported type found: {thing:?}")
328                        }
329                    })
330                    .collect::<String>())
331            })
332        }
333    }
334}
335
336/// Wrapper trait to allow for dynamic dispatch of raggable tools
337pub trait ToolEmbeddingDyn: ToolDyn {
338    fn context(&self) -> serde_json::Result<serde_json::Value>;
339
340    fn embedding_docs(&self) -> Vec<String>;
341}
342
343impl<T> ToolEmbeddingDyn for T
344where
345    T: ToolEmbedding + 'static,
346{
347    fn context(&self) -> serde_json::Result<serde_json::Value> {
348        serde_json::to_value(self.context())
349    }
350
351    fn embedding_docs(&self) -> Vec<String> {
352        self.embedding_docs()
353    }
354}
355
356pub(crate) enum ToolType {
357    Simple(Box<dyn ToolDyn>),
358    Embedding(Box<dyn ToolEmbeddingDyn>),
359}
360
361impl ToolType {
362    pub fn name(&self) -> String {
363        match self {
364            ToolType::Simple(tool) => tool.name(),
365            ToolType::Embedding(tool) => tool.name(),
366        }
367    }
368
369    pub async fn definition(&self, prompt: String) -> ToolDefinition {
370        match self {
371            ToolType::Simple(tool) => tool.definition(prompt).await,
372            ToolType::Embedding(tool) => tool.definition(prompt).await,
373        }
374    }
375
376    pub async fn call(&self, args: String) -> Result<String, ToolError> {
377        match self {
378            ToolType::Simple(tool) => tool.call(args).await,
379            ToolType::Embedding(tool) => tool.call(args).await,
380        }
381    }
382}
383
384#[derive(Debug, thiserror::Error)]
385pub enum ToolSetError {
386    /// Error returned by the tool
387    #[error("ToolCallError: {0}")]
388    ToolCallError(#[from] ToolError),
389
390    /// Could not find a tool
391    #[error("ToolNotFoundError: {0}")]
392    ToolNotFoundError(String),
393
394    // TODO: Revisit this
395    #[error("JsonError: {0}")]
396    JsonError(#[from] serde_json::Error),
397
398    /// Tool call was interrupted. Primarily useful for agent multi-step/turn prompting.
399    #[error("Tool call interrupted")]
400    Interrupted,
401}
402
403/// A struct that holds a set of tools
404#[derive(Default)]
405pub struct ToolSet {
406    pub(crate) tools: HashMap<String, ToolType>,
407}
408
409impl ToolSet {
410    /// Create a new ToolSet from a list of tools
411    pub fn from_tools(tools: Vec<impl ToolDyn + 'static>) -> Self {
412        let mut toolset = Self::default();
413        tools.into_iter().for_each(|tool| {
414            toolset.add_tool(tool);
415        });
416        toolset
417    }
418
419    /// Create a toolset builder
420    pub fn builder() -> ToolSetBuilder {
421        ToolSetBuilder::default()
422    }
423
424    /// Check if the toolset contains a tool with the given name
425    pub fn contains(&self, toolname: &str) -> bool {
426        self.tools.contains_key(toolname)
427    }
428
429    /// Add a tool to the toolset
430    pub fn add_tool(&mut self, tool: impl ToolDyn + 'static) {
431        self.tools
432            .insert(tool.name(), ToolType::Simple(Box::new(tool)));
433    }
434
435    /// Adds a boxed tool to the toolset. Useful for situations when dynamic dispatch is required.
436    pub fn add_tool_boxed(&mut self, tool: Box<dyn ToolDyn>) {
437        self.tools.insert(tool.name(), ToolType::Simple(tool));
438    }
439
440    pub fn delete_tool(&mut self, tool_name: &str) {
441        let _ = self.tools.remove(tool_name);
442    }
443
444    /// Merge another toolset into this one
445    pub fn add_tools(&mut self, toolset: ToolSet) {
446        self.tools.extend(toolset.tools);
447    }
448
449    pub(crate) fn get(&self, toolname: &str) -> Option<&ToolType> {
450        self.tools.get(toolname)
451    }
452
453    pub async fn get_tool_definitions(&self) -> Result<Vec<ToolDefinition>, ToolSetError> {
454        let mut defs = Vec::new();
455        for tool in self.tools.values() {
456            let def = tool.definition(String::new()).await;
457            defs.push(def);
458        }
459        Ok(defs)
460    }
461
462    /// Call a tool with the given name and arguments
463    pub async fn call(&self, toolname: &str, args: String) -> Result<String, ToolSetError> {
464        if let Some(tool) = self.tools.get(toolname) {
465            tracing::info!(target: "rig",
466                "Calling tool {toolname} with args:\n{}",
467                serde_json::to_string_pretty(&args).unwrap()
468            );
469            Ok(tool.call(args).await?)
470        } else {
471            Err(ToolSetError::ToolNotFoundError(toolname.to_string()))
472        }
473    }
474
475    /// Get the documents of all the tools in the toolset
476    pub async fn documents(&self) -> Result<Vec<completion::Document>, ToolSetError> {
477        let mut docs = Vec::new();
478        for tool in self.tools.values() {
479            match tool {
480                ToolType::Simple(tool) => {
481                    docs.push(completion::Document {
482                        id: tool.name(),
483                        text: format!(
484                            "\
485                            Tool: {}\n\
486                            Definition: \n\
487                            {}\
488                        ",
489                            tool.name(),
490                            serde_json::to_string_pretty(&tool.definition("".to_string()).await)?
491                        ),
492                        additional_props: HashMap::new(),
493                    });
494                }
495                ToolType::Embedding(tool) => {
496                    docs.push(completion::Document {
497                        id: tool.name(),
498                        text: format!(
499                            "\
500                            Tool: {}\n\
501                            Definition: \n\
502                            {}\
503                        ",
504                            tool.name(),
505                            serde_json::to_string_pretty(&tool.definition("".to_string()).await)?
506                        ),
507                        additional_props: HashMap::new(),
508                    });
509                }
510            }
511        }
512        Ok(docs)
513    }
514
515    /// Convert tools in self to objects of type ToolSchema.
516    /// This is necessary because when adding tools to the EmbeddingBuilder because all
517    /// documents added to the builder must all be of the same type.
518    pub fn schemas(&self) -> Result<Vec<ToolSchema>, EmbedError> {
519        self.tools
520            .values()
521            .filter_map(|tool_type| {
522                if let ToolType::Embedding(tool) = tool_type {
523                    Some(ToolSchema::try_from(&**tool))
524                } else {
525                    None
526                }
527            })
528            .collect::<Result<Vec<_>, _>>()
529    }
530}
531
532#[derive(Default)]
533pub struct ToolSetBuilder {
534    tools: Vec<ToolType>,
535}
536
537impl ToolSetBuilder {
538    pub fn static_tool(mut self, tool: impl ToolDyn + 'static) -> Self {
539        self.tools.push(ToolType::Simple(Box::new(tool)));
540        self
541    }
542
543    pub fn dynamic_tool(mut self, tool: impl ToolEmbeddingDyn + 'static) -> Self {
544        self.tools.push(ToolType::Embedding(Box::new(tool)));
545        self
546    }
547
548    pub fn build(self) -> ToolSet {
549        ToolSet {
550            tools: self
551                .tools
552                .into_iter()
553                .map(|tool| (tool.name(), tool))
554                .collect(),
555        }
556    }
557}
558
559#[cfg(test)]
560mod tests {
561    use serde_json::json;
562
563    use super::*;
564
565    fn get_test_toolset() -> ToolSet {
566        let mut toolset = ToolSet::default();
567
568        #[derive(Deserialize)]
569        struct OperationArgs {
570            x: i32,
571            y: i32,
572        }
573
574        #[derive(Debug, thiserror::Error)]
575        #[error("Math error")]
576        struct MathError;
577
578        #[derive(Deserialize, Serialize)]
579        struct Adder;
580
581        impl Tool for Adder {
582            const NAME: &'static str = "add";
583            type Error = MathError;
584            type Args = OperationArgs;
585            type Output = i32;
586
587            async fn definition(&self, _prompt: String) -> ToolDefinition {
588                ToolDefinition {
589                    name: "add".to_string(),
590                    description: "Add x and y together".to_string(),
591                    parameters: json!({
592                        "type": "object",
593                        "properties": {
594                            "x": {
595                                "type": "number",
596                                "description": "The first number to add"
597                            },
598                            "y": {
599                                "type": "number",
600                                "description": "The second number to add"
601                            }
602                        },
603                        "required": ["x", "y"]
604                    }),
605                }
606            }
607
608            async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
609                let result = args.x + args.y;
610                Ok(result)
611            }
612        }
613
614        #[derive(Deserialize, Serialize)]
615        struct Subtract;
616
617        impl Tool for Subtract {
618            const NAME: &'static str = "subtract";
619            type Error = MathError;
620            type Args = OperationArgs;
621            type Output = i32;
622
623            async fn definition(&self, _prompt: String) -> ToolDefinition {
624                serde_json::from_value(json!({
625                    "name": "subtract",
626                    "description": "Subtract y from x (i.e.: x - y)",
627                    "parameters": {
628                        "type": "object",
629                        "properties": {
630                            "x": {
631                                "type": "number",
632                                "description": "The number to subtract from"
633                            },
634                            "y": {
635                                "type": "number",
636                                "description": "The number to subtract"
637                            }
638                        },
639                        "required": ["x", "y"]
640                    }
641                }))
642                .expect("Tool Definition")
643            }
644
645            async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
646                let result = args.x - args.y;
647                Ok(result)
648            }
649        }
650
651        toolset.add_tool(Adder);
652        toolset.add_tool(Subtract);
653        toolset
654    }
655
656    #[tokio::test]
657    async fn test_get_tool_definitions() {
658        let toolset = get_test_toolset();
659        let tools = toolset.get_tool_definitions().await.unwrap();
660        assert_eq!(tools.len(), 2);
661    }
662
663    #[test]
664    fn test_tool_deletion() {
665        let mut toolset = get_test_toolset();
666        assert_eq!(toolset.tools.len(), 2);
667        toolset.delete_tool("add");
668        assert!(!toolset.contains("add"));
669        assert_eq!(toolset.tools.len(), 1);
670    }
671}
rig/tool/mod.rs

rig/tool/
mod.rs
