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

Annotations only declare readOnlyHint, so the description carries most of the behavioral burden and does so with non-obvious, high-value context: results differ by connection age, and reconnected workspaces surface private channels via the person's channels:read/groups:read scopes even without the bot. It stops short of describing result ordering or how multiple workspaces are merged/limited in the response.

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?

Front-loads purpose and scope in the first clause, then layers permissions nuance and the filter rule with no filler. The permissions sentence is long and somewhat dense, which slightly hurts scannability but each clause carries real information.

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?

For a read-only, zero-required-param listing tool with no output schema, the description covers scope, filtering, workspace selection, permission-dependent result variance, and next steps. An agent has everything needed to call it and interpret the outcome.

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 the baseline is 3. The description restates the query substring and accounts subset semantics already documented in the schema and adds no format, syntax, or edge-case detail beyond it.

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 and resource ('List/search Slack channels') with precise scope ('across ALL connected workspaces, or a subset via accounts'). It also names the downstream siblings (list_channel_members, read_channel) so an agent can place it in the workflow without opening another schema.

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?

Explicitly tells when to use each parameter mode ('query … omit to list everything', 'accounts … omit for every connected workspace') and routes the agent onward via 'Use the returned ids with list_channel_members or read_channel'. When-to-use and what-to-do-next are both covered.

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