Skip to main content
Glama
fullselfbrowsing

FSB (Full Self-Browsing)

Official
by fullselfbrowsing
OverviewSchemaSourceRelated ServersDiscussionsAdmin
JavaScript
Local

insert_text

Insert text into the focused editable field via CDP at the caret, or append at the end and replace all content; target a field with a CSS selector. Canvas editors must be focused first.

Instructions

Insert text through CDP at the caret by default. Use position end to append or replace_all to replace an editable field; selector can identify that field. Canvas editors require focus first. Related: type_text, double_click_at, click_at. Multi-agent: agent-scoped tabs; cross-agent reject with TAB_NOT_OWNED; cap configurable (default 8, 1-64). RETURNS change_report: when this tool runs, the response includes a change_report field with a compact diff of what the action mutated (URL, dialogs_opened, nodes_added, nodes_removed, attrs_changed, inputs_changed, focus_shift). Use this to learn the consequence without calling read_page next. If the report exceeds the size cap, change_report.truncated:true and change_report_hint are set; call read_page for the full state.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
textYesText to insert at current cursor position via CDP
clientYesAllowlisted client label. Validated against the shared v0.9.36 server/extension allowlist (see mcp/src/tools/visual-session.ts -- MCP_VISUAL_CLIENT_LABELS). Required.
tab_idNoOptional. Tab id this action targets. Omit when the calling agent owns exactly one tab; pass to disambiguate when the agent owns multiple. Single-tab agents and legacy popup/sidepanel/autopilot do not need to pass this.
is_finalNoWhen true, the visual session clears immediately after this tool resolves. Optional (default false).
positionNoInsertion position; defaults to caret.
selectorNoOptional CSS selector identifying exactly one editable field.
visual_reasonYesShort human-readable reason shown in the overlay (for example, "Logging in to GitHub"). Required.

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

A4.1/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and does so well: it discloses multi-agent tab scoping, the cross-agent rejection error (TAB_NOT_OWNED), a configurable cap (default 8, range 1-64), and a detailed change_report return contract including truncation behavior. This is unusually rich behavioral context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core action, then usage variants, then related tools, then multi-agent and return-value detail. Dense but every sentence is relevant; the change_report block is verbose but serves a real purpose since no output schema exists.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema exists, so the description must explain what comes back, and it does via the change_report field list and truncation fallback. Combined with usage, prerequisites, and multi-agent constraints, an agent has everything needed to call it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the parameters are already documented. The description adds some meaning to position values (caret default, end appends, replace_all replaces) and the selector's role, but most parameter detail is redundant with the schema. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Insert text through CDP') and clarifies the default target (caret). It hints at the difference from siblings by listing related tools (type_text, double_click_at, click_at), but does not sharply draw the boundary between itself and type_text.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear usage context: default caret insertion, position=end to append, replace_all to replace a field, and the prerequisite that canvas editors require focus first. It names related tools but never explicitly says when to prefer insert_text over type_text, leaving that distinction implicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

Other Tools