The model-facing web tool suite — `web_search` and `web_fetch` — over the [web capability seam](../web/README.md) (`ctx.web`). It owns model-facing concerns only: tool names, JSON schemas, snake_case argument names, prompt sections, the result-count bound, result formatting, HTML→markdown presentation, and `presentCall`. All web access goes through `ctx.web`; this package never imports a concrete provider. Neither tool exposes a model-facing timeout — each tool's cooperative tool-call budget is declared here via config (`fetchTimeoutMs`/`searchTimeoutMs`, attached as `ToolDefinition.timeoutMs`) and enforced by [`@deepseek-ai/dsh-timeout-policy`](../../timeout/timeout-policy/README.md) (a `tools/execute` wrapper); each tool just forwards `exec.signal` to the seam.
| `web_search` | `query` (string) | Discovery. Returns an optional answer plus source URLs. `max_results` is **not** model-facing — the tool sets the bound (the `searchMaxResults` config, default 8) and passes it to the seam. |
| `web_fetch` | `url` (string) | Retrieves a specific URL. HTML bodies are rendered to markdown (turndown with GFM tables/strikethrough); text bodies pass through. A non-2xx status is reported, not an error. The tool-call timeout is deployment policy (`dsh-timeout-policy`), not a model argument. |
The normalized seam results are also the canonical tool values: `WebSearchResult` and `WebFetchResult`. Native renderers preserve the answer/source and fetched-body text below; provider search/body caps remain acquisition limits rather than presentation-only truncation.
| `fetchMaxOutputChars` | `200000` | Cap on source characters converted synchronously and on one complete `web_fetch` output (header, rendered body, and footer); a cut body gets the truncation notice when it fits. |
`fetchTimeoutMs`/`searchTimeoutMs` declare each tool's cooperative timeout budget (attached as `ToolDefinition.timeoutMs`), enforced by [`@deepseek-ai/dsh-timeout-policy`](../../timeout/timeout-policy/README.md); the model-facing schema exposes no timeout argument. `fetchMaxOutputChars` bounds both synchronous conversion work and the complete rendered result: only that many source characters are converted, and the header, converted prefix, and truncation notice are then capped together. The default leaves headroom above the local provider's 100,000-character body cap, but rendered expansion can still make the final bound truncate the result.
Tool registration follows product **enablement**, not backend availability. A tool stays visible even when its selected provider is missing, misconfigured, ambiguous, or temporarily unavailable; the seam resolves the provider at execution time and execution fails with a structured `WebError` (e.g. `WEB_PROVIDER_UNAVAILABLE`, `WEB_PROVIDER_AMBIGUOUS`), which `ToolRegistry.execute()` turns into an error tool result the model can read and hooks/UI can route on. This keeps the model schema stable without making plugin load order, credential state, or HMR timing part of the model-facing contract. To remove a web tool entirely, disable it here in config.
The tool never calls a provider's `available()` and never enumerates providers — its only execution path is `ctx.web.search()` / `ctx.web.fetch()`, and provider unavailability reaches it as the structured `WebError` codes selection throws at execution time. Provider selection stays entirely inside the seam, with one owner.
Search and fetch contribute the web-search and web-fetch guidance below. A scoped tool restriction does not remove these independently registered sections.
Use the web_search tool to discover current information on the web. It returns an optional answer plus a list of source URLs. Follow up with web_fetch when you need the full content of a specific result, and cite the relevant URLs as markdown links.
Use the web_fetch tool to retrieve the content of a specific HTTP(S) URL (for example a result from web_search). It returns the page content decoded to text. Cite the URL as a markdown link when you use its content.
Fixed guidance cost per request for each config-enabled tool, even when a restriction hides its schema.
#### KV Cache effect
Prefix-stable while enabled tools, scope, and guidance text are unchanged. Config enablement or plugin lifecycle may invalidate reuse from the first changed prompt section; scoped schema restrictions do not remove it.
The model sees the generated [`web_search` and `web_fetch` schemas](../../../docs/tool-catalog.md#deepseek-aidsh-tool-web). Result-count and timeout budgets are deployment settings, not model arguments.
Fixed schema cost per request; config disablement removes both schema and guidance, while a scoped restriction removes only the schema.
#### KV Cache effect
Prefix-stable while definitions and visibility are unchanged. Config enablement, plugin lifecycle, or scoped restrictions may invalidate reuse from the first changed schema token.
The optional provider-owned answer is followed by `Sources:` and data-dependent lines shaped exactly `- [<title-or-url>](<url>)`, optionally suffixed ` — <snippet> (<publishedAt>)`. With neither answer nor sources the result says `No results found.` A capped list adds `(Showing the first <count> sources. Refine the query for more.)`; every result ends `Cite the relevant URLs above as markdown links in your answer.`
A successful fetch is exactly `Fetched <finalUrl> (HTTP <statusCode>)`, a blank line, and the provider-owned decoded body. Truncation adds a blank line and `(Content truncated. Fetch a more specific URL or section for the full text.)`; failures become `Error: <message>`. Queries and URLs remain in call history.
Provider caps bound body size; retained call arguments and results are resent until compaction, and timeout policy can replace a late result with a short error.
- **HTML→markdown conversion degrades on inputs GFM cannot safely represent** — [turndown](https://github.com/mixmark-io/turndown) (with GFM tables/strikethrough) converts at most `fetchMaxOutputChars` source characters through a real DOM. A conservative 512-level lexical guard passes deeply or ambiguously nested bodies through as raw HTML, conversion exceptions do the same, and table `colspan` is ignored because GFM has no spanning-cell representation; these bounds avoid blocking the event loop or expanding output from an untrusted numeric attribute ([Agent Note](../../../.agents/notes/implemented/simplification/2026-07-26-turndown-for-tool-web-html-markdown.md)).
- **The model-facing surface is minimal by design, with promotions deferred** — `max_results` stays a config bound (not a model argument), and `web_fetch` takes only `url` (no `format`/`prompt`/LLM-summarization mode); both are named later steps in [the seam Agent Note](../../../.agents/notes/implemented/architecture/2026-06-24-web-capability-seam.md).
- **No web-specific permission policy** — both tools execute without requesting `ctx.approval`; a deployment that needs confirmation must add a `tools/pre-execute` policy, and the package does not define persistent URL/domain grants.
