This is the documentation for v2 — looking for the v1 documentation?
MCP TypeScript SDK

Appearance

MCP TypeScript SDK (V2) / @modelcontextprotocol/client / ext/skills/skillsClient

ext/skills/skillsClient ​

Classes ​

SkillsClient ​

Defined in: packages/client/src/ext/skills/skillsClient.ts:151

Host side of the MCP Skills extension (SEP-2640): lists, gets and reads a server's skills, and verifies every file against the server's entry. Approval, origin tagging and loading policy stay with the host.

Example ​

ts
const skills = new SkillsClient(client);
const { skills: entries } = await skills.list();
const manifest = await skills.read(entries[0]!);

Constructors ​

Constructor ​

new SkillsClient(client, options?): SkillsClient

Defined in: packages/client/src/ext/skills/skillsClient.ts:155

Parameters ​
client ​

Client

options? ​

SkillsClientOptions = {}

Returns ​

SkillsClient

Accessors ​

directoryRead ​
Get Signature ​

get directoryRead(): boolean

Defined in: packages/client/src/ext/skills/skillsClient.ts:168

The server serves resources/directory/read.

Returns ​

boolean

supported ​
Get Signature ​

get supported(): boolean

Defined in: packages/client/src/ext/skills/skillsClient.ts:161

The server declared the extension (and resources, under enforceStrictCapabilities). false before connect.

Returns ​

boolean

Methods ​

get() ​

get(uri, options?): Promise<{ cacheScope?: "public" | "private"; skill: {[key: string]: unknown; _meta?: Record<string, unknown>; frontmatter: {[key: string]: unknown; description: string; name: string; }; resources: "dynamic" | object[]; uri: string; }; ttlMs?: number; }>

Defined in: packages/client/src/ext/skills/skillsClient.ts:206

One skill by its SKILL.md URI, listed or not, with the result's caching fields on 2026-07-28. Throws if the server returns an invalid entry or another skill.

Parameters ​
uri ​

string

options? ​

RequestOptions

Returns ​

Promise<{ cacheScope?: "public" | "private"; skill: {[key: string]: unknown; _meta?: Record<string, unknown>; frontmatter: {[key: string]: unknown; description: string; name: string; }; resources: "dynamic" | object[]; uri: string; }; ttlMs?: number; }>

list() ​

list(params?, options?): Promise<SkillListing>

Defined in: packages/client/src/ext/skills/skillsClient.ts:180

Lists the server's skills, walking every page unless given a cursor (bounded by the client's listMaxPages). Throws an SdkError naming every invalid entry, and every copy of a repeated URI; with skipInvalid, returns them in invalid instead. A 2026-07-28 page without ttlMs and cacheScope throws either way. On a server without the extension: an empty listing.

Parameters ​
params? ​
cursor? ​

string

options? ​

RequestOptions

Returns ​

Promise<SkillListing>

read() ​

read(skill, ref?, options?): Promise<SkillFile>

Defined in: packages/client/src/ext/skills/skillsClient.ts:236

Reads one file of skill and verifies it. ref is a path relative to the skill's root (references/FORMS.md) or an absolute URI; the default is the skill's own SKILL.md; a fragment is ignored. The file must be listed in the entry (checked before any request, however either side percent-encodes the name) and is requested by the entry's URI; its size and digest must match; for the skill's own SKILL.md the frontmatter must also equal the entry's. A copy from the client's response cache that fails a check is fetched once more with cacheMode: 'refresh'. "dynamic" skills skip the listing, size and digest checks (verified: false) but not the frontmatter. Pass entries from SkillsClient.list or SkillsClient.get; an invalid entry throws a TypeError before any request.

Parameters ​
skill ​
_meta? ​

Record<string, unknown> = ...

frontmatter ​

{[key: string]: unknown; description: string; name: string; } = SkillFrontmatterSchema

The SKILL.md frontmatter, verbatim.

frontmatter.description ​

string = ...

frontmatter.name ​

string = ...

resources ​

"dynamic" | object[] = SkillResourcesSchema

Every file of the skill, or "dynamic".

uri ​

string = ...

Resource URI of the skill's SKILL.md.

ref? ​

string

options? ​

CacheableRequestOptions

Returns ​

Promise<SkillFile>

Throws ​

when a check fails.

readDirectory() ​

readDirectory(uri, options?): Promise<{ cacheScope?: "public" | "private"; resources: object[]; ttlMs?: number; }>

Defined in: packages/client/src/ext/skills/skillsClient.ts:307

The direct children of a skill directory, every page walked, with the first page's caching fields on 2026-07-28. Needs directoryRead.

Parameters ​
uri ​

string

options? ​

RequestOptions

Returns ​

Promise<{ cacheScope?: "public" | "private"; resources: object[]; ttlMs?: number; }>

Interfaces ​

SkillFile ​

Defined in: packages/client/src/ext/skills/skillsClient.ts:56

A skill file as read and checked by SkillsClient.read.

Properties ​

body? ​

optional body?: string

Defined in: packages/client/src/ext/skills/skillsClient.ts:69

The skill's own SKILL.md only: the markdown after the frontmatter.

bytes ​

bytes: Uint8Array

Defined in: packages/client/src/ext/skills/skillsClient.ts:61

Exactly the bytes the entry's digest covers.

frontmatter? ​

optional frontmatter?: Record<string, unknown>

Defined in: packages/client/src/ext/skills/skillsClient.ts:67

The skill's own SKILL.md only: its parsed frontmatter, equal to the entry's.

mimeType? ​

optional mimeType?: string

Defined in: packages/client/src/ext/skills/skillsClient.ts:59

text? ​

optional text?: string

Defined in: packages/client/src/ext/skills/skillsClient.ts:63

When the server sent text (always, for the skill's own SKILL.md).

uri ​

uri: string

Defined in: packages/client/src/ext/skills/skillsClient.ts:58

The URI requested: the entry's spelling of the file; for "dynamic" skills, the resolved ref in its normalised form.

verified ​

verified: boolean

Defined in: packages/client/src/ext/skills/skillsClient.ts:65

Size and digest were checked. false only for "dynamic" skills.

SkillListing ​

Defined in: packages/client/src/ext/skills/skillsClient.ts:46

What list() returns: the valid entries, the refused ones (only with skipInvalid), and the first page's caching fields.

Properties ​

cacheScope? ​

optional cacheScope?: "public" | "private"

Defined in: packages/client/src/ext/skills/skillsClient.ts:52

invalid ​

invalid: InvalidSkillEntry[]

Defined in: packages/client/src/ext/skills/skillsClient.ts:48

nextCursor? ​

optional nextCursor?: string

Defined in: packages/client/src/ext/skills/skillsClient.ts:50

Only when list() was given a cursor (one page); a full walk has none.

skills ​

skills: object[]

Defined in: packages/client/src/ext/skills/skillsClient.ts:47

Index Signature ​

[key: string]: unknown

_meta? ​

optional _meta?: Record<string, unknown>

frontmatter ​

frontmatter: object = SkillFrontmatterSchema

The SKILL.md frontmatter, verbatim.

Index Signature ​

[key: string]: unknown

frontmatter.description ​

description: string

frontmatter.name ​

name: string

resources ​

resources: "dynamic" | object[] = SkillResourcesSchema

Every file of the skill, or "dynamic".

uri ​

uri: string

Resource URI of the skill's SKILL.md.

ttlMs? ​

optional ttlMs?: number

Defined in: packages/client/src/ext/skills/skillsClient.ts:51

SkillsClientOptions ​

Defined in: packages/client/src/ext/skills/skillsClient.ts:35

Properties ​

parseFrontmatter? ​

optional parseFrontmatter?: (yaml) => Record<string, unknown>

Defined in: packages/client/src/ext/skills/skillsClient.ts:40

Parses the YAML between a SKILL.md's --- lines (BOM and CRLF removed) for verification, instead of the built-in parser (YAML 1.2 core-schema typing).

Parameters ​
yaml ​

string

Returns ​

Record<string, unknown>

skipInvalid? ​

optional skipInvalid?: boolean

Defined in: packages/client/src/ext/skills/skillsClient.ts:42

Return invalid skills/list entries in invalid instead of throwing. Default false: list() throws on any.