A search round goes back with and without a local `tool_use` after its blocks: the endpoint takes both, and the model answers from the results it already holds. With the blocks stripped it calls its own earlier answer fabricated instead. The note sits where the ordering decision lives, so the shape needs no re-probe.
`provider_blocks` means something only to the surface that produced them (Anthropic `thinking` / server-tool blocks). A session that switched surface would otherwise send those dicts to a chat-completions provider as an assistant-message key it does not know; the request normalization drops the field, on a copy, so the history keeps it.
Streaming is the default path: `thinking` fragments, a `server_tool_use`'s `partial_json` query and a `web_search_tool_result`'s entries arrive as separate SSE events, so the blocks the round has to hand back exist only as fragments. The dispatch rebuilds each one from its start payload (field for field, under the stream's own names) plus the fragments that follow, and passes it to the loop as a chunk; the loop copies it onto the round's message, where a round that kept only those blocks counts as payload rather than an empty completion.
The thinking text streams as reasoning as it arrives — the search query and the signature go back with the round only.
DeepSeek's Anthropic compat answers a hosted search inside the turn: the response carries the `thinking` that picked the query, the `server_tool_use`, and the `web_search_tool_result`. The response mapping kept text and tool_use only, so the round lost its evidence — and the `thinking` signature, which only the provider can verify, could not go back at all. `AssistantChatMessage.provider_blocks` carries those blocks as raw JSON now (`thinking` text *and* signature, the query, the result entries with an `encrypted_content` the API rejects when trimmed) and the assistant turn hands them back first, ahead of its text and tool_use blocks; `thinking` also lands in `reasoning_content`, so the chain of thought streams as reasoning like every other surface's.
`AnthropicRawContentBlock` names the provider fields a streamed block carries, and `AnthropicServerToolUseContent` keeps the `caller` metadata the wire sends.
The ``responses_bridge`` bullet records that ``response.reasoning_text.done`` repeats the fragments: the loop streams each part once, and the round's message still carries the whole chain of thought back to the API.
DeepSeek's Responses stream sends ``response.reasoning_text.delta`` fragments and then ``response.reasoning_text.done`` carrying the whole chain of thought those fragments spelled out. The loop folded a full delta into the round — it replaces the fragments, and that is what the assistant message hands back to the API — but streamed every delta verbatim, so the chain of thought was printed twice: once as it arrived and again as the ``.done`` text.
A full delta now streams only a tail the fragments did not cover, and nothing at all when it merely repeats them; a round whose fragments never arrived still streams the full text once. The message keeps the complete text either way.
``web_search`` is composed by the CLI host rather than the builtin catalog, so it had no ``_PRETTY_LINES`` entry and fell back to the ``[tool] …`` / ``[tool ok] …`` whole lines. It now leads with ``* Web Search '<query>' `` (the query as a 60-character preview, like the ask and skill subjects) and lands on the hit count — or on ``(no results)`` when every source came up empty, an emptiness the tool reports as ``error: the search found nothing`` and which is therefore not shown as a failure. A real error still prints in red with its message.
The guard test that keeps a builtin tool from shipping without a renderer now checks this host-composed tool too, since a catalog walk cannot see it.
``search_sources`` (a provider list, ``["deepseek", "bing"]`` by default,
``[]`` to not offer the tool at all) names what the local ``web_search`` tool
searches with, in fallback order: ``search_in_order`` asks each source in turn
and keeps the first answer, so a source that errors — a rate limit, a rejected
key — or finds nothing hands over to the next instead of failing the tool. The
handler reports the failures only when every source came up empty.
The Bing leg answers with its RSS results (``?format=rss``), which need no key
and carry a description — the snippet DeepSeek's own index does not hand out —
and it goes through the ``fetch`` client, so the SSRF and host-grant policy
applies to it too (a host that binds tool instance state, as the CLI does).
``provider_tools`` reached the effective provider only for the OpenAI preset,
so a DeepSeek ``provider_tools`` in TOML was dropped on the way — and the preset
defaulted to none, leaving search unavailable for every convention.
DeepSeek now defaults to ``[{type="web_search"}]`` like OpenAI does (``[]``
turns it off) and its list reaches the agent: the Anthropic convention runs the
hosted search inside the response, the Responses and chat conventions get the
local ``web_search`` tool (see ``config.routing.local_web_search``).
The tools list gains the ``web_search`` entry (what it returns, when the CLI
registers it), and the provider-tools bullet says DeepSeek's preset asks for no
hosted tool by default.
Only DeepSeek's Anthropic-compatible surface runs a hosted ``web_search``: the
Responses and chat-completions surfaces answer "I can't browse the web" with
``{"type": "web_search"}`` and with the server-tool shape alike, so a DeepSeek
provider that talks them had no search at all.
``config.routing.local_web_search`` decides per provider: a DeepSeek provider
whose ``provider_tools`` ask for ``web_search`` and whose convention is not
``anthropic`` gets the local tool (``tools/net/search.py``), which asks the
search-capable endpoint behind the scenes and hands the model one ``title —
url`` line per hit — read a page with ``fetch``, the bodies stay server-side.
DeepSeek's preset asks for no hosted tool by default, so this stays opt-in.
DeepSeek runs ``web_search`` inside a turn — the request declares the server
tool, the response carries a ``server_tool_use`` per query and the
``web_search_tool_result`` it produced — so a search is one ``/messages`` call
whose hits are read out of the content blocks. The turn stops as soon as it has
searched (a live probe with 64 output tokens spent all of them before the search
and returned nothing, 512 answers with the hits).
Hits carry a title, a URL and an ``encrypted_content`` only the index can read,
so the hit list is all a caller gets: the page bodies stay server-side.
The ``messages_bridge`` bullet says a server tool is the surface's own business
(only ``tool_use`` becomes a local call), the provider-tools bullet says the
Messages surface declares its own definition, the ``anthropic/model.py`` bullet
lists the blocks that now decode, and the file map says as much.
The compat opens with the question alone (``message_start`` reports 165 tokens)
and puts what the search then pulled in on ``message_delta`` (12468); merging
preferred the earlier value, so the CLI's context gauge and the auto-compact
threshold ran ~12k short of the request. The larger of the two wins now (output
tokens are the delta's cumulative count either way).
NCBM