# @deepseek-ai/dsh-tool-skill The model-facing skill catalog and `skill` tool. Requires `ctx.tools` and `ctx.skills` (`inject: ['tools', 'skills']`). ## Session catalog The plugin injects one durable user-role `` catalog at the first `agent/step` of a live session. It resolves skills for the calling session's cwd, forwards the step abort signal to discovery, and lists only sorted `name` and `description` entries; skill bodies, paths, sources, providers, and `whenToUse` hints remain outside the catalog. The catalog is omitted when no model-invocable skills are available, and also when that agent's tool view restricts away the shipped `skill` tool or resolves a same-name scoped shadow instead. This exact-definition check keeps prompt guidance, the model-visible schema, and executable dispatch aligned. `catalogDescriptionMaxLength` controls normalized, XML-escaped catalog descriptions. Its default is `500` and values must be integers of at least `3`, which reserves room for a truncation ellipsis. The catalog is a sourced `user/message` injected before the first request and retained in ordinary session history. ## Tool: `skill` | Arg | Type | Notes | |---|---|---| | `name` | string (required) | Exact kebab-case skill name from the available skills listing. | Execution uses the calling agent's `session.header.cwd` so workspace-sensitive providers resolve the winning skill. A successful call returns canonical `{ name, provider, resourceBase?, content }`, excluding catalog ranking and provider-internal machinery; its Native renderer produces one text result containing ``, ``, and ``. Resource guidance resolves only paths or URLs explicitly referenced by the instructions against `resourceBase`; scripts, references, and assets load on demand, and the result does not enumerate a skill directory. Local providers may supply a directory, while remote or embedded providers may supply a URL or opaque loading guidance. An unresolved name reports that the skill is unknown or no longer available. Invalid names and `disableModelInvocation: true` skills produce distinct error results. The tool does not call `agent.inject()` in v1. Its result is already recorded as the tool result and becomes available to the next model step without duplicating the content as synthetic context. ## Model Experience ### Session catalog #### What the model sees If model-invocable skills exist and this exact `skill` tool is visible, the agent receives the catalog template below, with one data-dependent entry per sorted skill. The catalog is one durable user-role message. ##### Skill catalog template ```markdown A skill is a reusable set of task-specific instructions. The following skills are available in this session: - ``: If the user names a skill, or the task clearly matches a skill's description, call the `skill` tool with the exact skill name before taking task actions. Load all applicable skills, then follow their full instructions. This catalog contains summaries only; do not infer or follow a skill's instructions until it has been loaded. ``` #### Token effect Repeated input cost scales with skill count and `catalogDescriptionMaxLength`; no catalog tokens are sent when the list is empty or the tool is hidden or shadowed. #### KV Cache effect Append-only after the existing reusable prefix. A new or resumed instance with different providers, skills, descriptions, visibility, or catalog limits may affect cache reuse from the newly appended catalog position. ### Tool schema #### What the model sees The model sees the generated [`skill` schema](../../../docs/tool-catalog.md#deepseek-aidsh-tool-skill). #### Token effect Fixed schema cost per request where the tool is visible. #### KV Cache effect Prefix-stable while the tool definition and visibility are unchanged. Shadowing, restrictions, or plugin lifecycle changes may invalidate reuse from this schema. ### Tool result #### What the model sees A successful call uses the result template and the provider-managed, directory, URL, or opaque resource guidance below. ##### Skill result template ```markdown ``` ##### Provider-managed resource guidance ```markdown Resources for this skill are managed by provider "". Load referenced resources only as needed. ``` ##### Directory resource guidance ```markdown Base directory for this skill: Resolve relative paths mentioned by this skill against the base directory before using them. Load referenced resources only as needed. ``` ##### URL resource guidance ```markdown Base URL for this skill: Resolve relative URLs mentioned by this skill against the base URL before using them. Load referenced resources only as needed. ``` ##### Opaque resource guidance ```markdown Resources for this skill: Load referenced resources only as needed. ``` #### Token effect Loaded instructions are data-dependent tool-result tokens, resent on later steps until compaction; no duplicate `agent.inject()` copy is made. #### KV Cache effect Append-only; newly visible content follows the reusable request prefix and does not invalidate existing KV-cache entries. ### Tool errors #### What the model sees Invalid or stale selections return exactly `Error: invalid skill name ""`, `Error: skill "" is unknown or no longer available`, or `Error: skill "" is not available for model invocation`. Provider-thrown lookup text is data-dependent and receives the same `Error: ` wrapper. #### Token effect Only a failing call adds these retained tokens. #### KV Cache effect Append-only; newly visible content follows the reusable request prefix and does not invalidate existing KV-cache entries. ## Known Limitations and Deferred Work - **The catalog omits `whenToUse`, source, and provider metadata** — routing is based only on name and a capped description; `whenToUse` remains provider metadata and is not rendered by the loaded wrapper either. - **Loaded instruction bodies have no size cap** — a provider can return a skill large enough to consume substantial next-step context; only catalog descriptions are truncated. - **Resources are guidance, not attachments** — the tool reports a base directory/URL/opaque hint but neither enumerates nor fetches referenced files for the model. - **Loading is one-shot text** — there is no partial, streaming, or cached-content handle when a remote provider is slow or a skill body is large.