Tools changedspecification/2025-11-25/server/tools
Nearest release: v2.1.305, published under an hour before upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Upstream edited this page at 20 Oct 2026 20:02 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 22 Oct 2026 20:37 UTC.
Upstream edited
Recorded here
Lines+11added
Lines−11removed
From line
49
where the diff opens
First seen
26 Aug 2026
this site's first read of the page
Recorded edits3to this page, all time
The whole hunk
from line 49, old and new numbered
/
from line 49
4949### Listing Tools
5050
5151To discover available tools, clients send a `tools/list` request. This operation supports
52[pagination](/specification/2025-11-25/server/utilities/pagination).
52[pagination](/specification/2025-11-25/server/utilities/pagination.md).
5353
5454**Request:**
5555
from line 190
190190* `description`: Human-readable description of functionality
191191* `icons`: Optional array of icons for display in user interfaces
192192* `inputSchema`: JSON Schema defining expected parameters
193 * Follows the [JSON Schema usage guidelines](/specification/2025-11-25/basic#json-schema-usage)
193 * Follows the [JSON Schema usage guidelines](/specification/2025-11-25/basic.md#json-schema-usage)
194194 * Defaults to 2020-12 if no `$schema` field is present
195195 * **MUST** be a valid JSON Schema object (not `null`)
196196 * For tools with no parameters, use one of these valid approaches:
from line 197
197197 * `{ "type": "object", "additionalProperties": false }` - **Recommended**: explicitly accepts only empty objects
198198 * `{ "type": "object" }` - accepts any object (including with properties)
199199* `outputSchema`: Optional JSON Schema defining expected output structure
200 * Follows the [JSON Schema usage guidelines](/specification/2025-11-25/basic#json-schema-usage)
200 * Follows the [JSON Schema usage guidelines](/specification/2025-11-25/basic.md#json-schema-usage)
201201 * Defaults to 2020-12 if no `$schema` field is present
202202* `annotations`: Optional properties describing tool behavior
203203* `execution`: Optional object describing execution-related properties
204 * `taskSupport`: Indicates whether this tool supports [task-augmented execution](/specification/2025-11-25/basic/utilities/tasks#tool-level-negotiation). Values: `"forbidden"` (default), `"optional"`, or `"required"`
204 * `taskSupport`: Indicates whether this tool supports [task-augmented execution](/specification/2025-11-25/basic/utilities/tasks.md#tool-level-negotiation). Values: `"forbidden"` (default), `"optional"`, or `"required"`
205205
206206> [!WARNING]
207207>
from line 231
231231>
232232> All content types (text, image, audio, resource links, and embedded resources)
233233> support optional
234> [annotations](/specification/2025-11-25/server/resources#annotations) that
234> [annotations](/specification/2025-11-25/server/resources.md#annotations) that
235235> provide metadata about audience, priority, and modification times. This is the
236236> same annotation format used by resources and prompts.
237237
from line 270
270270
271271#### Resource Links
272272
273A tool **MAY** return links to [Resources](/specification/2025-11-25/server/resources), to provide additional context
273A tool **MAY** return links to [Resources](/specification/2025-11-25/server/resources.md), to provide additional context
274274or data. In this case, the tool will return a URI that can be subscribed to or fetched by the client:
275275
276276```json theme={null}
from line 283
283283}
284284```
285285
286Resource links support the same [Resource annotations](/specification/2025-11-25/server/resources#annotations) as regular resources to help clients understand how to use them.
286Resource links support the same [Resource annotations](/specification/2025-11-25/server/resources.md#annotations) as regular resources to help clients understand how to use them.
287287
288288> [!NOTE]
289289>
from line 292
292292
293293#### Embedded Resources
294294
295[Resources](/specification/2025-11-25/server/resources) **MAY** be embedded to provide additional context
296or data using a suitable [URI scheme](./resources#common-uri-schemes). Servers that use embedded resources **SHOULD** implement the `resources` capability:
295[Resources](/specification/2025-11-25/server/resources.md) **MAY** be embedded to provide additional context
296or data using a suitable [URI scheme](/specification/2025-11-25/server/resources.md#common-uri-schemes). Servers that use embedded resources **SHOULD** implement the `resources` capability:
297297
298298```json theme={null}
299299{
from line 311
311311}
312312```
313313
314Embedded resources support the same [Resource annotations](/specification/2025-11-25/server/resources#annotations) as regular resources to help clients understand how to use them.
314Embedded resources support the same [Resource annotations](/specification/2025-11-25/server/resources.md#annotations) as regular resources to help clients understand how to use them.
315315
316316#### Structured Content
317317
from line 455
455455
4564561. **Protocol Errors**: Standard JSON-RPC errors for issues like:
457457 * Unknown tools
458 * Malformed requests (requests that fail to satisfy [CallToolRequest schema](/specification/2025-11-25/schema#calltoolrequest))
458 * Malformed requests (requests that fail to satisfy [CallToolRequest schema](/specification/2025-11-25/schema.md#calltoolrequest))
459459 * Server errors
460460
4614612. **Tool Execution Errors**: Reported in tool results with `isError: true`:
No line in this hunk matches that.