What each tool switch actually turns on: CRM writes, helpdesk tickets, knowledge search, SMS and email, timers, MCP servers and memories.
A voice agent with no tools can only talk. Tools are what let it look things up, write things down and send things — during the call, while the caller is still on the line. This article covers the Tools tab: what the groups mean, which switches matter, and the ones people forget.
Everything here is on the agent's Tools tab (Tools & Capabilities), except Tools during calls, which is on Setup.
agents:voice:manage permission.An agent gets a tool only if it is ticked here. There is no implicit set; if the agent "won't do" something, this tab is the first place to look.
Five are marked as recommended for most agents: send-sms,
send-email, web-search, retrieval_search and
save-update-user.
flowchart TB
A["Tools tab selection"] --> B["In-call telephony<br/>transfer · cold_transfer · send-dtmf<br/>voicemail_detection · manage_timer"]
A --> C["CRM & contacts<br/>save-update-user · notes · tasks · deals"]
A --> D["Knowledge & search<br/>Tenant Brain · vector search · web search"]
A --> E["Messaging<br/>send-email · send-sms"]
A --> F["Helpdesk<br/>create·reply·update ticket<br/>CSAT"]
A --> G["Operations & duty<br/>duty-check · duty_notify"]
A --> H["Integrations<br/>Google · Microsoft · calendar · maps · Workiz · ERS"]
A --> I["MCP servers<br/>your own connected tools"]
Voice & Calls — the in-call mechanics: warm and cold transfer, keypad tones, voicemail detection, timers. See Transfers, Forwarding and the Duty Roster.
CRM & Contacts — save-update-user identifies and updates the caller,
plus the verbs to add notes, create tasks and deals, and move lifecycle
stages. Everything in this group is pinned to the caller the agent
identified — the agent cannot redirect a CRM write to somebody else's record.
Knowledge & Search — Tenant Brain reads and searches, document
(file-search / vector) search, web search, and fetching the detail of a
prior interaction.
Messaging — send-email and send-sms. Both use the identity you set in
the Sending identity card on this tab (from name, from address, signature,
SMS number).
Helpdesk & Tickets — create, read, list, update and reply to tickets, and record a satisfaction score. These are caller-scoped: they only ever touch the caller's own tickets, and replies are public replies. Status and priority changes follow your Helpdesk AI governance policy and may wait in the approvals queue rather than applying immediately.
Helpdesk tools need
save-update-usertoo. Tickets are filed under a contact, and that is the tool the agent identifies the caller with. Enable a helpdesk tool without it and the tab warns you: the agent will not be able to open tickets at all.
Operations & Duty — duty lookups and notifications.
Integrations & Other — Google Workspace, Microsoft 365, calendar, maps, and industry packs such as Workiz and roadside assistance, where configured.
Two tools are always available and are not listed: the agent can always tell the time, and it can always record an opt-out if a caller asks not to be contacted again.
Both let the agent answer from your material; they are not the same thing.
| Tenant Brain | Vector stores | |
|---|---|---|
| Holds | Governed, versioned concepts your team reviewed and published | Documents you uploaded |
| Best for | Policies, playbooks, FAQs, pricing rules — anything that must be right | Manuals, spec sheets, long reference PDFs |
| Citation | The call shows which concepts were used | Retrieved passages |
| Who changes it | Published through review; agents can propose, not publish | Whoever manages the store |
For anything a caller might act on, prefer the Brain. A policy that lives only in a PDF gets retrieved differently every time; a published concept is one governed answer.
Vector Stores has its own block lower on the tab: "Select the vector
stores this agent can search." It is required when using the file-search
tool — enabling the tool without selecting a store leaves the agent with
nothing to search. The header shows "N of M selected".
Tenant Brain tools include draft-only proposal ability: the agent can suggest a concept from something it learned on a call, and a human publishes it. That is the loop that makes next month's calls better than this month's. See Tenant Brain.
An agent with read_knowledge or search_knowledge ticked sees a map of
the Tenant Brain in its instructions (one line per published entry) and reads
entries by path; when it cannot name a path, the brain's advisor picks one. The
Tenant Brain block on the Tools tab, right under the tools list, sizes that
map and each read for this agent. Every value has a platform default, shown as
a placeholder until you set one.
| Setting | What it does | Default |
|---|---|---|
| Include the brain's map in this agent's instructions | Off, the agent keeps its brain tools but gets no map and has to list the brain before it can read a path. | On |
| Map lines | Lean is path, title, tags and aliases; Full adds each entry's description so the agent can tell siblings apart without a read. | Lean |
| Map budget (characters) | How much of the map the prompt may carry. The map trims to fit, whole sections first, and never drops silently. | 12,000 |
| Read budget (characters) | What one read may return. The first entry is trimmed before anything is dropped. | 8,000 |
| Entries per lookup | How many entries one read_knowledge or search_knowledge call returns at most. |
3 |
| When a lookup names no path | Serve the advisor's pick returns the best entry's content in one round trip; Return the shortlist hands the agent the candidates to choose from. Both run the advisor. | Serve |
Every character of the map and of a read is time to first word on a call, so the block's Recommended for voice agents line suggests a lean map of 8,000 characters, reads of 4,000 and 2 entries per lookup; Apply recommended sets them in one click. The line under the block reads back what the agent will get. The same block, with its own recommendation, is on every agent type's form.
MCP Servers connects the agent to tools you host or subscribe to, beyond what ships with the platform. Pick the servers this agent may use, and — where a server offers many — the individual tools from each.
Everything about MCP is subject to the Tools during calls switch below.
Memories → Enable Memories gives the agent per-contact memory that survives between calls: what this person prefers, what was agreed last time, the thing they always have to explain. With it on you can also choose which memory types the agent may read and write.
Memories are not part of a browser test run, so a memory-dependent behaviour has to be checked with Place a test call or a real call.
Cross-Agent Enrichment ("Pull recent interactions from other agent types into this agent's context") is the setting that makes a caller feel recognised rather than processed: the agent opens the call already knowing the person emailed on Tuesday and used the website chat this morning.
It also enables the agent's ability to fetch the full detail of one of those interactions when the summary is not enough.
Keep the count low. Each interaction is context the model reads on every turn, so a high number costs latency on the whole call in exchange for history the agent may never need.
Below the tools, Optional Prompt Components switches on reusable prompt text — platform components and your workspace's own. System components are always included and are not listed here. Your workspace's components are created by a tenant admin at Settings (the gear icon) → Agents & AI → Prompt Components. See Instructions, Goals and Scheduled Prompts.
A component of kind Section is a situation — instructions for one moment
in a call that the agent reads with read_instructions only when the moment
arrives. Sections are picked on the agent's Conversation tab, in the Situations
card, not here. See
Situations.
On the Setup tab, Tools during calls → Off: testing without tools runs calls without the tools and MCP servers ticked here and without voicemail-detection instructions. The agent still talks; it cannot act.
It is the right setting for rehearsing wording without sending real emails, and it is the most common reason an agent that "worked yesterday" suddenly does nothing. While it is Off, the header shows Call tools off, the count beside Tools & Capabilities reads 0 active (what will run), and this tab says Tools are off during calls above the tool list, with a link that takes you to the switch. Your ticks are kept ("1 of 12 selected" still counts them): switch it back On and every tool and MCP server works again, as it was.
This is worth stating plainly, because it surprises people during testing: when a tool fires, it fires. Emails are sent, texts go out, tickets are created, connected systems are written to — including from the browser test panel, which says so in its own description.
When you are still iterating, switch Tools during calls to Off, or test with your own contact record and your own phone number.
On a Gemini 3.8 Live agent the Tools tab gains Tools on live-audio calls: one row per enabled tool with what the caller hears while it runs — Wait for the result (the agent pauses), Keep talking · interrupt (the result cuts in as soon as it lands), Keep talking · at the next pause (the agent finishes its sentence first) or Keep talking · silently (the result simply enters the agent's context; if the agent said nothing when it called the tool, it speaks again once the result is in, so the caller is never left in silence). The defaults by kind: lookups and sends at the next pause, saves silently, transfer / end call / voicemail-detected wait, because the call cannot continue past them — change those only if the agent should finish its sentence first. On the extended-thinking variant every tool keeps talking, whatever is set. Whichever you pick, the agent is told per tool never to say a result is done before it has it.
While a "keep talking" tool runs, the agent is told to use the time: it starts a lookup as soon as it has what the lookup needs, and in the same breath says what it is checking and asks the question that moves the call forward ("Let me check that address. While I do, what day suits you for the pickup?"), so the caller's answer fills the wait. Meanwhile it carries on with whatever does not need the result. If a lookup has run for about two and a half seconds with the agent silent, the platform gives it a turn to do exactly that, so the line never goes quiet for long. The call record shows how long each tool left the line silent.
file-search. Platform rules
forbid inventing facts, so the usual symptom is a refusal to answer rather
than an invention — if you are getting inventions, check the instructions
are not pushing it to answer regardless.save-update-user is not enabled.
Tickets need an identified contact.file-search returns nothing. No vector store is selected in the
Vector Stores block.