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sendbird

by io.usefulapi

List messages

sendbird_list_messages
Read-only

List messages in a channel, anchored at a timestamp or message id. Provide EITHER message_ts (unix ms) OR message_id. Platform API: GET /{channel_type}/{channel_url}/messages. Returns { messages[] }.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
includeNoInclude the anchor message itself.
reverseNoReturn in reverse chronological order.
user_idsNoComma-separated sender user ids to filter on.
message_idNoAnchor message id. Provide this OR message_ts.
message_tsNoAnchor timestamp in unix milliseconds. Provide this OR message_id.
next_limitNoNumber of messages after the anchor, 0-200.
prev_limitNoNumber of messages before the anchor, 0-200.
channel_urlYesChannel URL (percent-encoded automatically).
channel_typeYesChannel type: group_channels (member-based) or open_channels (public, participant-based).
custom_typesNoComma-separated message custom types to filter on.
message_typeNoFilter by message type: MESG (text), FILE, or ADMM (admin).

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. First observed

TDQS

A4.4/5.0
Behavior4/5

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

readOnlyHint=true already signals a safe read, lowering the bar. The description adds context beyond the annotation: the HTTP GET endpoint (confirming read-only behavior), the anchoring semantics, and the return shape ('Returns { messages[] }'). No contradiction with annotations.

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

Conciseness5/5

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

Four short sentences, each earning its place: purpose, exclusive-anchor rule, underlying REST endpoint, and return format. The most critical constraint (EITHER/OR) is front-loaded in the second sentence; no filler and no repetition of schema content.

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

Completeness4/5

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

Despite 11 parameters and no output schema, the description covers the two largest gaps: the mutually exclusive anchor parameters and the return shape ({ messages[] }). Required params (channel_type, channel_url) are visible in the schema and implied by the endpoint URL, so nothing critical is missing for correct invocation.

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

Parameters4/5

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

Schema coverage is 100%, so baseline is 3. The description adds real value beyond the schema by stating the mutual-exclusion rule ('Provide EITHER message_ts OR message_id') that the schema does not enforce, and by confirming the unix-ms unit for message_ts.

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

Purpose5/5

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

States a precise verb+resource ('List messages in a channel') and adds the distinguishing anchor mechanism ('anchored at a timestamp or message id'). This clearly separates it from siblings like sendbird_list_group_channels, sendbird_list_open_channels, and sendbird_list_users, which list channels or users rather than messages.

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?

Provides clear operational context: the tool lists messages within a specific channel, with concrete anchoring guidance ('Provide EITHER message_ts OR message_id') and required channel parameters implied by the endpoint URI. It does not explicitly name alternatives or state when-not-to-use, but no sibling could plausibly be confused with this operation.

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

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TDQS

A4/5.0
Disambiguation5/5

Each tool maps to a distinct resource-action pair (users, group/open channels, members, messages), and the get/list/create/update/send verbs keep boundaries clear. The raw GET escape hatch is explicitly limited to unwrapped paths, so it does not create meaningful overlap.

Naming Consistency5/5

All tools follow the predictable sendbird_<verb>_<resource> snake_case pattern, with consistent verbs like create, get, list, update, and send. The generic sendbird_request is a deliberate exception rather than a naming inconsistency.

Tool Count5/5

14 tools is within the ideal range and each tool covers a coherent piece of Sendbird's chat platform: users, channels, members, messages, and a raw GET fallback. There are no redundant or filler tools.

Completeness3/5

The set covers common read/list flows and some mutations, but lifecycle coverage has notable gaps: group channels can be created and read but not updated/deleted, messages can be sent and listed but not updated/deleted, and users have no delete operation. The raw GET tool is read-only and cannot compensate for these missing write operations.

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