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;
14use std::fmt;
15
16use futures::Future;
17use serde::{Deserialize, Serialize};
18
19use crate::{
20    completion::{self, ToolDefinition},
21    embeddings::{embed::EmbedError, tool::ToolSchema},
22    wasm_compat::{WasmBoxedFuture, WasmCompatSend, WasmCompatSync},
23};
24
25#[derive(Debug, thiserror::Error)]
26pub enum ToolError {
27    #[cfg(not(target_family = "wasm"))]
28    /// Error returned by the tool
29    ToolCallError(#[from] Box<dyn std::error::Error + Send + Sync>),
30
31    #[cfg(target_family = "wasm")]
32    /// Error returned by the tool
33    ToolCallError(#[from] Box<dyn std::error::Error>),
34    /// Error caused by a de/serialization fail
35    JsonError(#[from] serde_json::Error),
36}
37
38impl fmt::Display for ToolError {
39    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
40        match self {
41            ToolError::ToolCallError(e) => {
42                let error_str = e.to_string();
43                // This is required due to being able to use agents as tools
44                // which means it is possible to get recursive tool call errors
45                if error_str.starts_with("ToolCallError: ") {
46                    write!(f, "{}", error_str)
47                } else {
48                    write!(f, "ToolCallError: {}", error_str)
49                }
50            }
51            ToolError::JsonError(e) => write!(f, "JsonError: {e}"),
52        }
53    }
54}
55
56/// Trait that represents a simple LLM tool
57///
58/// # Example
59/// ```
60/// use rig::{
61///     completion::ToolDefinition,
62///     tool::{ToolSet, Tool},
63/// };
64///
65/// #[derive(serde::Deserialize)]
66/// struct AddArgs {
67///     x: i32,
68///     y: i32,
69/// }
70///
71/// #[derive(Debug, thiserror::Error)]
72/// #[error("Math error")]
73/// struct MathError;
74///
75/// #[derive(serde::Deserialize, serde::Serialize)]
76/// struct Adder;
77///
78/// impl Tool for Adder {
79///     const NAME: &'static str = "add";
80///
81///     type Error = MathError;
82///     type Args = AddArgs;
83///     type Output = i32;
84///
85///     async fn definition(&self, _prompt: String) -> ToolDefinition {
86///         ToolDefinition {
87///             name: "add".to_string(),
88///             description: "Add x and y together".to_string(),
89///             parameters: serde_json::json!({
90///                 "type": "object",
91///                 "properties": {
92///                     "x": {
93///                         "type": "number",
94///                         "description": "The first number to add"
95///                     },
96///                     "y": {
97///                         "type": "number",
98///                         "description": "The second number to add"
99///                     }
100///                 }
101///             })
102///         }
103///     }
104///
105///     async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
106///         let result = args.x + args.y;
107///         Ok(result)
108///     }
109/// }
110/// ```
111pub trait Tool: Sized + WasmCompatSend + WasmCompatSync {
112    /// The name of the tool. This name should be unique.
113    const NAME: &'static str;
114
115    /// The error type of the tool.
116    type Error: std::error::Error + WasmCompatSend + WasmCompatSync + 'static;
117    /// The arguments type of the tool.
118    type Args: for<'a> Deserialize<'a> + WasmCompatSend + WasmCompatSync;
119    /// The output type of the tool.
120    type Output: Serialize;
121
122    /// A method returning the name of the tool.
123    fn name(&self) -> String {
124        Self::NAME.to_string()
125    }
126
127    /// A method returning the tool definition. The user prompt can be used to
128    /// tailor the definition to the specific use case.
129    fn definition(
130        &self,
131        _prompt: String,
132    ) -> impl Future<Output = ToolDefinition> + WasmCompatSend + WasmCompatSync;
133
134    /// The tool execution method.
135    /// Both the arguments and return value are a String since these values are meant to
136    /// be the output and input of LLM models (respectively)
137    fn call(
138        &self,
139        args: Self::Args,
140    ) -> impl Future<Output = Result<Self::Output, Self::Error>> + WasmCompatSend;
141}
142
143/// Trait that represents an LLM tool that can be stored in a vector store and RAGged
144pub trait ToolEmbedding: Tool {
145    type InitError: std::error::Error + WasmCompatSend + WasmCompatSync + 'static;
146
147    /// Type of the tool' context. This context will be saved and loaded from the
148    /// vector store when ragging the tool.
149    /// This context can be used to store the tool's static configuration and local
150    /// context.
151    type Context: for<'a> Deserialize<'a> + Serialize;
152
153    /// Type of the tool's state. This state will be passed to the tool when initializing it.
154    /// This state can be used to pass runtime arguments to the tool such as clients,
155    /// API keys and other configuration.
156    type State: WasmCompatSend;
157
158    /// A method returning the documents that will be used as embeddings for the tool.
159    /// This allows for a tool to be retrieved from multiple embedding "directions".
160    /// If the tool will not be RAGged, this method should return an empty vector.
161    fn embedding_docs(&self) -> Vec<String>;
162
163    /// A method returning the context of the tool.
164    fn context(&self) -> Self::Context;
165
166    /// A method to initialize the tool from the context, and a state.
167    fn init(state: Self::State, context: Self::Context) -> Result<Self, Self::InitError>;
168}
169
170/// Wrapper trait to allow for dynamic dispatch of simple tools
171pub trait ToolDyn: WasmCompatSend + WasmCompatSync {
172    fn name(&self) -> String;
173
174    fn definition<'a>(&'a self, prompt: String) -> WasmBoxedFuture<'a, ToolDefinition>;
175
176    fn call<'a>(&'a self, args: String) -> WasmBoxedFuture<'a, Result<String, ToolError>>;
177}
178
179impl<T: Tool> ToolDyn for T {
180    fn name(&self) -> String {
181        self.name()
182    }
183
184    fn definition<'a>(&'a self, prompt: String) -> WasmBoxedFuture<'a, ToolDefinition> {
185        Box::pin(<Self as Tool>::definition(self, prompt))
186    }
187
188    fn call<'a>(&'a self, args: String) -> WasmBoxedFuture<'a, Result<String, ToolError>> {
189        Box::pin(async move {
190            match serde_json::from_str(&args) {
191                Ok(args) => <Self as Tool>::call(self, args)
192                    .await
193                    .map_err(|e| ToolError::ToolCallError(Box::new(e)))
194                    .and_then(|output| {
195                        serde_json::to_string(&output).map_err(ToolError::JsonError)
196                    }),
197                Err(e) => Err(ToolError::JsonError(e)),
198            }
199        })
200    }
201}
202
203#[cfg(feature = "rmcp")]
204#[cfg_attr(docsrs, doc(cfg(feature = "rmcp")))]
205pub mod rmcp {
206    use crate::completion::ToolDefinition;
207    use crate::tool::ToolDyn;
208    use crate::tool::ToolError;
209    use crate::wasm_compat::WasmBoxedFuture;
210    use rmcp::model::RawContent;
211    use std::borrow::Cow;
212
213    #[derive(Clone)]
214    pub struct McpTool {
215        definition: rmcp::model::Tool,
216        client: rmcp::service::ServerSink,
217    }
218
219    impl McpTool {
220        pub fn from_mcp_server(
221            definition: rmcp::model::Tool,
222            client: rmcp::service::ServerSink,
223        ) -> Self {
224            Self { definition, client }
225        }
226    }
227
228    impl From<&rmcp::model::Tool> for ToolDefinition {
229        fn from(val: &rmcp::model::Tool) -> Self {
230            Self {
231                name: val.name.to_string(),
232                description: val.description.clone().unwrap_or(Cow::from("")).to_string(),
233                parameters: val.schema_as_json_value(),
234            }
235        }
236    }
237
238    impl From<rmcp::model::Tool> for ToolDefinition {
239        fn from(val: rmcp::model::Tool) -> Self {
240            Self {
241                name: val.name.to_string(),
242                description: val.description.clone().unwrap_or(Cow::from("")).to_string(),
243                parameters: val.schema_as_json_value(),
244            }
245        }
246    }
247
248    #[derive(Debug, thiserror::Error)]
249    #[error("MCP tool error: {0}")]
250    pub struct McpToolError(String);
251
252    impl From<McpToolError> for ToolError {
253        fn from(e: McpToolError) -> Self {
254            ToolError::ToolCallError(Box::new(e))
255        }
256    }
257
258    impl ToolDyn for McpTool {
259        fn name(&self) -> String {
260            self.definition.name.to_string()
261        }
262
263        fn definition(&self, _prompt: String) -> WasmBoxedFuture<'_, ToolDefinition> {
264            Box::pin(async move {
265                ToolDefinition {
266                    name: self.definition.name.to_string(),
267                    description: self
268                        .definition
269                        .description
270                        .clone()
271                        .unwrap_or(Cow::from(""))
272                        .to_string(),
273                    parameters: serde_json::to_value(&self.definition.input_schema)
274                        .unwrap_or_default(),
275                }
276            })
277        }
278
279        fn call(&self, args: String) -> WasmBoxedFuture<'_, Result<String, ToolError>> {
280            let name = self.definition.name.clone();
281            let arguments = serde_json::from_str(&args).unwrap_or_default();
282
283            Box::pin(async move {
284                let result = self
285                    .client
286                    .call_tool(rmcp::model::CallToolRequestParam {
287                        name,
288                        arguments,
289                        task: None,
290                    })
291                    .await
292                    .map_err(|e| McpToolError(format!("Tool returned an error: {e}")))?;
293
294                if let Some(true) = result.is_error {
295                    let error_msg = result
296                        .content
297                        .into_iter()
298                        .map(|x| x.raw.as_text().map(|y| y.to_owned()))
299                        .map(|x| x.map(|x| x.clone().text))
300                        .collect::<Option<Vec<String>>>();
301
302                    let error_message = error_msg.map(|x| x.join("\n"));
303                    if let Some(error_message) = error_message {
304                        return Err(McpToolError(error_message).into());
305                    } else {
306                        return Err(McpToolError("No message returned".to_string()).into());
307                    }
308                };
309
310                Ok(result
311                    .content
312                    .into_iter()
313                    .map(|c| match c.raw {
314                        rmcp::model::RawContent::Text(raw) => raw.text,
315                        rmcp::model::RawContent::Image(raw) => {
316                            format!("data:{};base64,{}", raw.mime_type, raw.data)
317                        }
318                        rmcp::model::RawContent::Resource(raw) => match raw.resource {
319                            rmcp::model::ResourceContents::TextResourceContents {
320                                uri,
321                                mime_type,
322                                text,
323                                ..
324                            } => {
325                                format!(
326                                    "{mime_type}{uri}:{text}",
327                                    mime_type = mime_type
328                                        .map(|m| format!("data:{m};"))
329                                        .unwrap_or_default(),
330                                )
331                            }
332                            rmcp::model::ResourceContents::BlobResourceContents {
333                                uri,
334                                mime_type,
335                                blob,
336                                ..
337                            } => format!(
338                                "{mime_type}{uri}:{blob}",
339                                mime_type = mime_type
340                                    .map(|m| format!("data:{m};"))
341                                    .unwrap_or_default(),
342                            ),
343                        },
344                        RawContent::Audio(_) => {
345                            panic!("Support for audio results from an MCP tool is currently unimplemented. Come back later!")
346                        }
347                        thing => {
348                            panic!("Unsupported type found: {thing:?}")
349                        }
350                    })
351                    .collect::<String>())
352            })
353        }
354    }
355}
356
357/// Wrapper trait to allow for dynamic dispatch of raggable tools
358pub trait ToolEmbeddingDyn: ToolDyn {
359    fn context(&self) -> serde_json::Result<serde_json::Value>;
360
361    fn embedding_docs(&self) -> Vec<String>;
362}
363
364impl<T> ToolEmbeddingDyn for T
365where
366    T: ToolEmbedding + 'static,
367{
368    fn context(&self) -> serde_json::Result<serde_json::Value> {
369        serde_json::to_value(self.context())
370    }
371
372    fn embedding_docs(&self) -> Vec<String> {
373        self.embedding_docs()
374    }
375}
376
377pub(crate) enum ToolType {
378    Simple(Box<dyn ToolDyn>),
379    Embedding(Box<dyn ToolEmbeddingDyn>),
380}
381
382impl ToolType {
383    pub fn name(&self) -> String {
384        match self {
385            ToolType::Simple(tool) => tool.name(),
386            ToolType::Embedding(tool) => tool.name(),
387        }
388    }
389
390    pub async fn definition(&self, prompt: String) -> ToolDefinition {
391        match self {
392            ToolType::Simple(tool) => tool.definition(prompt).await,
393            ToolType::Embedding(tool) => tool.definition(prompt).await,
394        }
395    }
396
397    pub async fn call(&self, args: String) -> Result<String, ToolError> {
398        match self {
399            ToolType::Simple(tool) => tool.call(args).await,
400            ToolType::Embedding(tool) => tool.call(args).await,
401        }
402    }
403}
404
405#[derive(Debug, thiserror::Error)]
406pub enum ToolSetError {
407    /// Error returned by the tool
408    #[error("ToolCallError: {0}")]
409    ToolCallError(#[from] ToolError),
410
411    /// Could not find a tool
412    #[error("ToolNotFoundError: {0}")]
413    ToolNotFoundError(String),
414
415    // TODO: Revisit this
416    #[error("JsonError: {0}")]
417    JsonError(#[from] serde_json::Error),
418
419    /// Tool call was interrupted. Primarily useful for agent multi-step/turn prompting.
420    #[error("Tool call interrupted")]
421    Interrupted,
422}
423
424/// A struct that holds a set of tools
425#[derive(Default)]
426pub struct ToolSet {
427    pub(crate) tools: HashMap<String, ToolType>,
428}
429
430impl ToolSet {
431    /// Create a new ToolSet from a list of tools
432    pub fn from_tools(tools: Vec<impl ToolDyn + 'static>) -> Self {
433        let mut toolset = Self::default();
434        tools.into_iter().for_each(|tool| {
435            toolset.add_tool(tool);
436        });
437        toolset
438    }
439
440    pub fn from_tools_boxed(tools: Vec<Box<dyn ToolDyn + 'static>>) -> Self {
441        let mut toolset = Self::default();
442        tools.into_iter().for_each(|tool| {
443            toolset.add_tool_boxed(tool);
444        });
445        toolset
446    }
447
448    /// Create a toolset builder
449    pub fn builder() -> ToolSetBuilder {
450        ToolSetBuilder::default()
451    }
452
453    /// Check if the toolset contains a tool with the given name
454    pub fn contains(&self, toolname: &str) -> bool {
455        self.tools.contains_key(toolname)
456    }
457
458    /// Add a tool to the toolset
459    pub fn add_tool(&mut self, tool: impl ToolDyn + 'static) {
460        self.tools
461            .insert(tool.name(), ToolType::Simple(Box::new(tool)));
462    }
463
464    /// Adds a boxed tool to the toolset. Useful for situations when dynamic dispatch is required.
465    pub fn add_tool_boxed(&mut self, tool: Box<dyn ToolDyn>) {
466        self.tools.insert(tool.name(), ToolType::Simple(tool));
467    }
468
469    pub fn delete_tool(&mut self, tool_name: &str) {
470        let _ = self.tools.remove(tool_name);
471    }
472
473    /// Merge another toolset into this one
474    pub fn add_tools(&mut self, toolset: ToolSet) {
475        self.tools.extend(toolset.tools);
476    }
477
478    pub(crate) fn get(&self, toolname: &str) -> Option<&ToolType> {
479        self.tools.get(toolname)
480    }
481
482    pub async fn get_tool_definitions(&self) -> Result<Vec<ToolDefinition>, ToolSetError> {
483        let mut defs = Vec::new();
484        for tool in self.tools.values() {
485            let def = tool.definition(String::new()).await;
486            defs.push(def);
487        }
488        Ok(defs)
489    }
490
491    /// Call a tool with the given name and arguments
492    pub async fn call(&self, toolname: &str, args: String) -> Result<String, ToolSetError> {
493        if let Some(tool) = self.tools.get(toolname) {
494            tracing::debug!(target: "rig",
495                "Calling tool {toolname} with args:\n{}",
496                serde_json::to_string_pretty(&args).unwrap()
497            );
498            Ok(tool.call(args).await?)
499        } else {
500            Err(ToolSetError::ToolNotFoundError(toolname.to_string()))
501        }
502    }
503
504    /// Get the documents of all the tools in the toolset
505    pub async fn documents(&self) -> Result<Vec<completion::Document>, ToolSetError> {
506        let mut docs = Vec::new();
507        for tool in self.tools.values() {
508            match tool {
509                ToolType::Simple(tool) => {
510                    docs.push(completion::Document {
511                        id: tool.name(),
512                        text: format!(
513                            "\
514                            Tool: {}\n\
515                            Definition: \n\
516                            {}\
517                        ",
518                            tool.name(),
519                            serde_json::to_string_pretty(&tool.definition("".to_string()).await)?
520                        ),
521                        additional_props: HashMap::new(),
522                    });
523                }
524                ToolType::Embedding(tool) => {
525                    docs.push(completion::Document {
526                        id: tool.name(),
527                        text: format!(
528                            "\
529                            Tool: {}\n\
530                            Definition: \n\
531                            {}\
532                        ",
533                            tool.name(),
534                            serde_json::to_string_pretty(&tool.definition("".to_string()).await)?
535                        ),
536                        additional_props: HashMap::new(),
537                    });
538                }
539            }
540        }
541        Ok(docs)
542    }
543
544    /// Convert tools in self to objects of type ToolSchema.
545    /// This is necessary because when adding tools to the EmbeddingBuilder because all
546    /// documents added to the builder must all be of the same type.
547    pub fn schemas(&self) -> Result<Vec<ToolSchema>, EmbedError> {
548        self.tools
549            .values()
550            .filter_map(|tool_type| {
551                if let ToolType::Embedding(tool) = tool_type {
552                    Some(ToolSchema::try_from(&**tool))
553                } else {
554                    None
555                }
556            })
557            .collect::<Result<Vec<_>, _>>()
558    }
559}
560
561#[derive(Default)]
562pub struct ToolSetBuilder {
563    tools: Vec<ToolType>,
564}
565
566impl ToolSetBuilder {
567    pub fn static_tool(mut self, tool: impl ToolDyn + 'static) -> Self {
568        self.tools.push(ToolType::Simple(Box::new(tool)));
569        self
570    }
571
572    pub fn dynamic_tool(mut self, tool: impl ToolEmbeddingDyn + 'static) -> Self {
573        self.tools.push(ToolType::Embedding(Box::new(tool)));
574        self
575    }
576
577    pub fn build(self) -> ToolSet {
578        ToolSet {
579            tools: self
580                .tools
581                .into_iter()
582                .map(|tool| (tool.name(), tool))
583                .collect(),
584        }
585    }
586}
587
588#[cfg(test)]
589mod tests {
590    use serde_json::json;
591
592    use super::*;
593
594    fn get_test_toolset() -> ToolSet {
595        let mut toolset = ToolSet::default();
596
597        #[derive(Deserialize)]
598        struct OperationArgs {
599            x: i32,
600            y: i32,
601        }
602
603        #[derive(Debug, thiserror::Error)]
604        #[error("Math error")]
605        struct MathError;
606
607        #[derive(Deserialize, Serialize)]
608        struct Adder;
609
610        impl Tool for Adder {
611            const NAME: &'static str = "add";
612            type Error = MathError;
613            type Args = OperationArgs;
614            type Output = i32;
615
616            async fn definition(&self, _prompt: String) -> ToolDefinition {
617                ToolDefinition {
618                    name: "add".to_string(),
619                    description: "Add x and y together".to_string(),
620                    parameters: json!({
621                        "type": "object",
622                        "properties": {
623                            "x": {
624                                "type": "number",
625                                "description": "The first number to add"
626                            },
627                            "y": {
628                                "type": "number",
629                                "description": "The second number to add"
630                            }
631                        },
632                        "required": ["x", "y"]
633                    }),
634                }
635            }
636
637            async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
638                let result = args.x + args.y;
639                Ok(result)
640            }
641        }
642
643        #[derive(Deserialize, Serialize)]
644        struct Subtract;
645
646        impl Tool for Subtract {
647            const NAME: &'static str = "subtract";
648            type Error = MathError;
649            type Args = OperationArgs;
650            type Output = i32;
651
652            async fn definition(&self, _prompt: String) -> ToolDefinition {
653                serde_json::from_value(json!({
654                    "name": "subtract",
655                    "description": "Subtract y from x (i.e.: x - y)",
656                    "parameters": {
657                        "type": "object",
658                        "properties": {
659                            "x": {
660                                "type": "number",
661                                "description": "The number to subtract from"
662                            },
663                            "y": {
664                                "type": "number",
665                                "description": "The number to subtract"
666                            }
667                        },
668                        "required": ["x", "y"]
669                    }
670                }))
671                .expect("Tool Definition")
672            }
673
674            async fn call(&self, args: Self::Args) -> Result<Self::Output, Self::Error> {
675                let result = args.x - args.y;
676                Ok(result)
677            }
678        }
679
680        toolset.add_tool(Adder);
681        toolset.add_tool(Subtract);
682        toolset
683    }
684
685    #[tokio::test]
686    async fn test_get_tool_definitions() {
687        let toolset = get_test_toolset();
688        let tools = toolset.get_tool_definitions().await.unwrap();
689        assert_eq!(tools.len(), 2);
690    }
691
692    #[test]
693    fn test_tool_deletion() {
694        let mut toolset = get_test_toolset();
695        assert_eq!(toolset.tools.len(), 2);
696        toolset.delete_tool("add");
697        assert!(!toolset.contains("add"));
698        assert_eq!(toolset.tools.len(), 1);
699    }
700}
rig/tool/mod.rs

rig/tool/
mod.rs
