List Channels

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered. The description adds one real behavioral fact — results are limited to the user's memberships, not all server channels — but says nothing about result volume, ordering, or pagination behavior for a list tool over a potentially large workspace.

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

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

A single front-loaded sentence with no filler or redundant restatement of the title. Nothing to trim.

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

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

An output schema exists, so return values needn't be described, and annotations cover the safety profile. However, for a 4-parameter filtered list tool the description says 'all channels' without signaling the filtering surface, which risks an agent treating it as an unfiltered dump and pulling DMs/category-restricted results unexpectedly.

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

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

Schema description coverage is 100%, so team_id, category, include_dm and include_muted are all documented in structured data; baseline 3 applies. The description adds no parameter context at all — notably it never hints that the list is filterable by team or sidebar category, nor that DMs are included by default.

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

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

States a specific verb (list) and resource (Mattermost channels) plus a meaningful scope qualifier: only channels the authenticated user is a member of. It does not distinguish itself from siblings like list_teams or get_direct_messages, which is the only thing keeping it from a 5.

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

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

There is no when-to-use guidance, no mention of alternatives (get_channel for a single channel, get_direct_messages for DMs, list_teams for teams), and no note that this is the entry point for discovering channels before calling get_channel_posts. Usage is only inferable from the verb.

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