feat(tools): Allow eventId on get_issue_breadcrumbs (#1224)

Let `get_issue_breadcrumbs` take an optional `eventId` so callers can
inspect breadcrumbs for more than the newest event in an issue. Omitted
values still resolve to `latest`.

**Event selection**

The tool and helper now call `getEventForIssue` with `eventId` (default
`latest`), matching the existing stacktrace tool pattern. Generated
tool/skill definitions were regenerated.

Fixes #1222

<!-- junior-request-attribution:start -->
Requested by **David Cramer**.
<!-- junior-request-attribution:end -->

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---------

Co-authored-by: sentry-junior[bot] <264270552+sentry-junior[bot]@users.noreply.github.com>
Co-authored-by: David Cramer <david@sentry.io>

Author: sentry-junior[bot]

packages/mcp-core/src/api-client/client.ts

@@ -3259,7 +3259,7 @@ export class SentryApiService {
     opts?: RequestOptions,
   ): Promise<Event> {
     const body = await this.requestJSON(
-      `/organizations/${organizationSlug}/issues/${issueId}/events/${eventId}/`,
+      `/organizations/${encodeURIComponent(organizationSlug)}/issues/${encodeURIComponent(issueId)}/events/${encodeURIComponent(eventId)}/`,
       undefined,
       opts,
     );

packages/mcp-core/src/internal/tool-helpers/breadcrumbs.ts

@@ -1,16 +1,19 @@
 import type { SentryApiService } from "../../api-client/index";
 
 /**
- * Fetches breadcrumbs from the latest event for an issue and formats them.
+ * Fetches breadcrumbs from an issue event and formats them.
+ * Defaults to the latest event when eventId is omitted.
  */
 export async function fetchAndFormatBreadcrumbs(
   apiService: SentryApiService,
   organizationSlug: string,
   issueId: string,
+  eventId: string = "latest",
 ): Promise<string> {
-  const event = await apiService.getLatestEventForIssue({
+  const event = await apiService.getEventForIssue({
     organizationSlug,
     issueId,
+    eventId,
   });
 
   const breadcrumbEntry = event.entries.find((e) => e.type === "breadcrumbs");
@@ -40,7 +43,7 @@ export function formatBreadcrumbs(
       "",
       `**Event ID**: ${eventId}`,
       "",
-      "No breadcrumbs found in the latest event for this issue.",
+      "No breadcrumbs found in this event for the issue.",
     ].join("\n");
   }
 

packages/mcp-core/src/schema.ts

@@ -237,7 +237,23 @@ export const ParamSentryGuide = z
       "Use either a platform (e.g., 'javascript', 'python') or platform/guide combination (e.g., 'javascript/nextjs', 'python/django').",
   );
 
-export const ParamEventId = z.string().trim().describe("The ID of the event.");
+export const ParamEventId = z
+  .string()
+  .trim()
+  .regex(
+    /^[0-9a-fA-F]{32}$/,
+    "Event ID must be a 32-character hexadecimal string",
+  )
+  .describe("The ID of the event. e.g. `c49541c747cb4d8aa3efb70ca5aba243`");
+
+/**
+ * Issue-scoped event selector used by tools that can target either a concrete
+ * event or the issue's latest event.
+ */
+export const ParamEventIdOrLatest = z
+  .union([z.literal("latest"), ParamEventId])
+  .default("latest")
+  .describe("The event ID for the issue, or `latest`. Defaults to `latest`.");
 
 export const ParamAttachmentId = z
   .string()

packages/mcp-core/src/skillDefinitions.json

@@ -69,7 +69,7 @@
       },
       {
         "name": "get_event_stacktrace",
-        "description": "Get a full thread stacktrace from a specific Sentry event.\n\nUse this tool when you need to:\n- Fetch the full stacktrace for a thread listed in issue details\n- Inspect a non-crashed thread from an event with multiple threads\n- Get Sentry's default selected thread stacktrace when no thread is specified\n\n<examples>\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123')\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='abc123', thread=259)\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', thread='main')\n</examples>\n\n<hints>\n- `thread` is optional. If omitted, this returns the same default thread Sentry selects: first crashed thread, then first thread with a stacktrace, then first thread.\n- Pass `thread` as a numeric Thread ID or exact thread Name from the issue details thread list.\n- If the issue details show only one useful thread, omit `thread`.\n</hints>",
+        "description": "Get a full thread stacktrace from a specific Sentry event.\n\nUse this tool when you need to:\n- Fetch the full stacktrace for a thread listed in issue details\n- Inspect a non-crashed thread from an event with multiple threads\n- Get Sentry's default selected thread stacktrace when no thread is specified\n\n<examples>\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123')\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='c49541c747cb4d8aa3efb70ca5aba243', thread=259)\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', thread='main')\n</examples>\n\n<hints>\n- `thread` is optional. If omitted, this returns the same default thread Sentry selects: first crashed thread, then first thread with a stacktrace, then first thread.\n- Pass `thread` as a numeric Thread ID or exact thread Name from the issue details thread list.\n- If the issue details show only one useful thread, omit `thread`.\n</hints>",
         "requiredScopes": ["event:read"]
       },
       {
@@ -79,7 +79,7 @@
       },
       {
         "name": "get_issue_breadcrumbs",
-        "description": "Get the breadcrumb trail from the latest event for a Sentry issue.\n\nUse this tool when you need to:\n- See the user and application actions leading up to an error\n- Inspect navigation, console, HTTP, and other breadcrumb events\n- Reconstruct the immediate context before an issue occurred\n\n<examples>\nget_issue_breadcrumbs(organizationSlug='my-org', issueId='PROJECT-123')\nget_issue_breadcrumbs(issueUrl='https://my-org.sentry.io/issues/PROJECT-123/')\n</examples>",
+        "description": "Get the breadcrumb trail from a Sentry issue event.\nDefaults to the latest event when eventId is omitted.\n\nUse this tool when you need to:\n- See the user and application actions leading up to an error\n- Inspect navigation, console, HTTP, and other breadcrumb events\n- Reconstruct the immediate context before an issue occurred\n- Compare breadcrumb trails across multiple events in the same issue\n\n<examples>\nget_issue_breadcrumbs(organizationSlug='my-org', issueId='PROJECT-123')\nget_issue_breadcrumbs(organizationSlug='my-org', issueId='PROJECT-123', eventId='c49541c747cb4d8aa3efb70ca5aba243')\nget_issue_breadcrumbs(issueUrl='https://my-org.sentry.io/issues/PROJECT-123/')\n</examples>",
         "requiredScopes": ["event:read"]
       },
       {
@@ -214,7 +214,7 @@
       },
       {
         "name": "get_event_stacktrace",
-        "description": "Get a full thread stacktrace from a specific Sentry event.\n\nUse this tool when you need to:\n- Fetch the full stacktrace for a thread listed in issue details\n- Inspect a non-crashed thread from an event with multiple threads\n- Get Sentry's default selected thread stacktrace when no thread is specified\n\n<examples>\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123')\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='abc123', thread=259)\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', thread='main')\n</examples>\n\n<hints>\n- `thread` is optional. If omitted, this returns the same default thread Sentry selects: first crashed thread, then first thread with a stacktrace, then first thread.\n- Pass `thread` as a numeric Thread ID or exact thread Name from the issue details thread list.\n- If the issue details show only one useful thread, omit `thread`.\n</hints>",
+        "description": "Get a full thread stacktrace from a specific Sentry event.\n\nUse this tool when you need to:\n- Fetch the full stacktrace for a thread listed in issue details\n- Inspect a non-crashed thread from an event with multiple threads\n- Get Sentry's default selected thread stacktrace when no thread is specified\n\n<examples>\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123')\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='c49541c747cb4d8aa3efb70ca5aba243', thread=259)\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', thread='main')\n</examples>\n\n<hints>\n- `thread` is optional. If omitted, this returns the same default thread Sentry selects: first crashed thread, then first thread with a stacktrace, then first thread.\n- Pass `thread` as a numeric Thread ID or exact thread Name from the issue details thread list.\n- If the issue details show only one useful thread, omit `thread`.\n</hints>",
         "requiredScopes": ["event:read"]
       },
       {
@@ -320,7 +320,7 @@
       },
       {
         "name": "get_event_stacktrace",
-        "description": "Get a full thread stacktrace from a specific Sentry event.\n\nUse this tool when you need to:\n- Fetch the full stacktrace for a thread listed in issue details\n- Inspect a non-crashed thread from an event with multiple threads\n- Get Sentry's default selected thread stacktrace when no thread is specified\n\n<examples>\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123')\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='abc123', thread=259)\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', thread='main')\n</examples>\n\n<hints>\n- `thread` is optional. If omitted, this returns the same default thread Sentry selects: first crashed thread, then first thread with a stacktrace, then first thread.\n- Pass `thread` as a numeric Thread ID or exact thread Name from the issue details thread list.\n- If the issue details show only one useful thread, omit `thread`.\n</hints>",
+        "description": "Get a full thread stacktrace from a specific Sentry event.\n\nUse this tool when you need to:\n- Fetch the full stacktrace for a thread listed in issue details\n- Inspect a non-crashed thread from an event with multiple threads\n- Get Sentry's default selected thread stacktrace when no thread is specified\n\n<examples>\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123')\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='c49541c747cb4d8aa3efb70ca5aba243', thread=259)\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', thread='main')\n</examples>\n\n<hints>\n- `thread` is optional. If omitted, this returns the same default thread Sentry selects: first crashed thread, then first thread with a stacktrace, then first thread.\n- Pass `thread` as a numeric Thread ID or exact thread Name from the issue details thread list.\n- If the issue details show only one useful thread, omit `thread`.\n</hints>",
         "requiredScopes": ["event:read"]
       },
       {
@@ -330,7 +330,7 @@
       },
       {
         "name": "get_issue_breadcrumbs",
-        "description": "Get the breadcrumb trail from the latest event for a Sentry issue.\n\nUse this tool when you need to:\n- See the user and application actions leading up to an error\n- Inspect navigation, console, HTTP, and other breadcrumb events\n- Reconstruct the immediate context before an issue occurred\n\n<examples>\nget_issue_breadcrumbs(organizationSlug='my-org', issueId='PROJECT-123')\nget_issue_breadcrumbs(issueUrl='https://my-org.sentry.io/issues/PROJECT-123/')\n</examples>",
+        "description": "Get the breadcrumb trail from a Sentry issue event.\nDefaults to the latest event when eventId is omitted.\n\nUse this tool when you need to:\n- See the user and application actions leading up to an error\n- Inspect navigation, console, HTTP, and other breadcrumb events\n- Reconstruct the immediate context before an issue occurred\n- Compare breadcrumb trails across multiple events in the same issue\n\n<examples>\nget_issue_breadcrumbs(organizationSlug='my-org', issueId='PROJECT-123')\nget_issue_breadcrumbs(organizationSlug='my-org', issueId='PROJECT-123', eventId='c49541c747cb4d8aa3efb70ca5aba243')\nget_issue_breadcrumbs(issueUrl='https://my-org.sentry.io/issues/PROJECT-123/')\n</examples>",
         "requiredScopes": ["event:read"]
       },
       {

packages/mcp-core/src/toolDefinitions.json

@@ -2321,7 +2321,8 @@
         },
         "eventId": {
           "type": "string",
-          "description": "The ID of the event."
+          "pattern": "^[0-9a-fA-F]{32}$",
+          "description": "The ID of the event. e.g. `c49541c747cb4d8aa3efb70ca5aba243`"
         },
         "attachmentId": {
           "default": null,
@@ -2356,7 +2357,7 @@
   },
   {
     "name": "get_event_stacktrace",
-    "description": "Get a full thread stacktrace from a specific Sentry event.\n\nUse this tool when you need to:\n- Fetch the full stacktrace for a thread listed in issue details\n- Inspect a non-crashed thread from an event with multiple threads\n- Get Sentry's default selected thread stacktrace when no thread is specified\n\n<examples>\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123')\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='abc123', thread=259)\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', thread='main')\n</examples>\n\n<hints>\n- `thread` is optional. If omitted, this returns the same default thread Sentry selects: first crashed thread, then first thread with a stacktrace, then first thread.\n- Pass `thread` as a numeric Thread ID or exact thread Name from the issue details thread list.\n- If the issue details show only one useful thread, omit `thread`.\n</hints>",
+    "description": "Get a full thread stacktrace from a specific Sentry event.\n\nUse this tool when you need to:\n- Fetch the full stacktrace for a thread listed in issue details\n- Inspect a non-crashed thread from an event with multiple threads\n- Get Sentry's default selected thread stacktrace when no thread is specified\n\n<examples>\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123')\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='c49541c747cb4d8aa3efb70ca5aba243', thread=259)\nget_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', thread='main')\n</examples>\n\n<hints>\n- `thread` is optional. If omitted, this returns the same default thread Sentry selects: first crashed thread, then first thread with a stacktrace, then first thread.\n- Pass `thread` as a numeric Thread ID or exact thread Name from the issue details thread list.\n- If the issue details show only one useful thread, omit `thread`.\n</hints>",
     "inputSchema": {
       "type": "object",
       "properties": {
@@ -2382,8 +2383,18 @@
         },
         "eventId": {
           "default": "latest",
-          "description": "The event ID for the issue. Defaults to `latest`.",
-          "type": "string"
+          "description": "The event ID for the issue, or `latest`. Defaults to `latest`.",
+          "anyOf": [
+            {
+              "type": "string",
+              "const": "latest"
+            },
+            {
+              "type": "string",
+              "pattern": "^[0-9a-fA-F]{32}$",
+              "description": "The ID of the event. e.g. `c49541c747cb4d8aa3efb70ca5aba243`"
+            }
+          ]
         },
         "thread": {
           "description": "Optional thread selector. Pass a numeric thread ID, or an exact thread name string. If omitted, returns the same default thread Sentry selects: first crashed thread, then first thread with a stacktrace, then first thread.",
@@ -2455,7 +2466,7 @@
   },
   {
     "name": "get_issue_breadcrumbs",
-    "description": "Get the breadcrumb trail from the latest event for a Sentry issue.\n\nUse this tool when you need to:\n- See the user and application actions leading up to an error\n- Inspect navigation, console, HTTP, and other breadcrumb events\n- Reconstruct the immediate context before an issue occurred\n\n<examples>\nget_issue_breadcrumbs(organizationSlug='my-org', issueId='PROJECT-123')\nget_issue_breadcrumbs(issueUrl='https://my-org.sentry.io/issues/PROJECT-123/')\n</examples>",
+    "description": "Get the breadcrumb trail from a Sentry issue event.\nDefaults to the latest event when eventId is omitted.\n\nUse this tool when you need to:\n- See the user and application actions leading up to an error\n- Inspect navigation, console, HTTP, and other breadcrumb events\n- Reconstruct the immediate context before an issue occurred\n- Compare breadcrumb trails across multiple events in the same issue\n\n<examples>\nget_issue_breadcrumbs(organizationSlug='my-org', issueId='PROJECT-123')\nget_issue_breadcrumbs(organizationSlug='my-org', issueId='PROJECT-123', eventId='c49541c747cb4d8aa3efb70ca5aba243')\nget_issue_breadcrumbs(issueUrl='https://my-org.sentry.io/issues/PROJECT-123/')\n</examples>",
     "inputSchema": {
       "type": "object",
       "properties": {
@@ -2483,6 +2494,21 @@
           "type": "string",
           "format": "uri",
           "description": "The URL of the issue. e.g. https://my-organization.sentry.io/issues/PROJECT-1Z43"
+        },
+        "eventId": {
+          "default": "latest",
+          "description": "The event ID for the issue, or `latest`. Defaults to `latest`.",
+          "anyOf": [
+            {
+              "type": "string",
+              "const": "latest"
+            },
+            {
+              "type": "string",
+              "pattern": "^[0-9a-fA-F]{32}$",
+              "description": "The ID of the event. e.g. `c49541c747cb4d8aa3efb70ca5aba243`"
+            }
+          ]
         }
       }
     },
@@ -2518,7 +2544,8 @@
         },
         "eventId": {
           "type": "string",
-          "description": "The ID of the event."
+          "pattern": "^[0-9a-fA-F]{32}$",
+          "description": "The ID of the event. e.g. `c49541c747cb4d8aa3efb70ca5aba243`"
         },
         "issueUrl": {
           "type": "string",

packages/mcp-core/src/tools/catalog/get-event-attachment.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import getEventAttachment from "./get-event-attachment.js";
 
 describe("get_event_attachment", () => {
@@ -110,7 +110,7 @@ describe("get_event_attachment", () => {
       {
         organizationSlug: "sentry-mcp-evals",
         projectSlug: "cloudflare-mcp",
-        eventId: "octet-stream-event-id",
+        eventId: "d49541c747cb4d8aa3efb70ca5aba244",
         attachmentId: "456",
         regionUrl: null,
       },

packages/mcp-core/src/tools/catalog/get-event-stacktrace.ts

@@ -6,6 +6,7 @@ import { defineTool } from "../../internal/tool-helpers/define";
 import { enhanceNotFoundError } from "../../internal/tool-helpers/enhance-error";
 import { ensureIssueWithinProjectConstraint } from "../../internal/tool-helpers/issue";
 import {
+  ParamEventIdOrLatest,
   ParamIssueShortId,
   ParamOrganizationSlug,
   ParamRegionUrl,
@@ -27,7 +28,7 @@ export default defineTool({
     "",
     "<examples>",
     "get_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123')",
-    "get_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='abc123', thread=259)",
+    "get_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', eventId='c49541c747cb4d8aa3efb70ca5aba243', thread=259)",
     "get_event_stacktrace(organizationSlug='my-org', issueId='PROJECT-123', thread='main')",
     "</examples>",
     "",
@@ -41,11 +42,7 @@ export default defineTool({
     organizationSlug: ParamOrganizationSlug,
     regionUrl: ParamRegionUrl.nullable().default(null),
     issueId: ParamIssueShortId,
-    eventId: z
-      .string()
-      .trim()
-      .default("latest")
-      .describe("The event ID for the issue. Defaults to `latest`."),
+    eventId: ParamEventIdOrLatest,
     thread: z
       .union([z.number().int(), z.string().trim().min(1)])
       .optional()