discord_read_messages

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

Annotations already declare readOnlyHint, so the safety profile is covered; the description adds the non-obvious behavioral facts that matter: the 100-message per-call cap, the backwards-paging recipe, and the required permissions. It stops short of any comment on rate limits or behavior when a channel is empty/inaccessible, keeping it off a 5.

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?

Three tightly packed sentences, front-loaded with scope and paging before moving to permissions and alternatives. The one wasted element is the enumeration of returned fields (id, author, content, timestamp, attachment count, pinned flag), which duplicates the output schema and is repeated nowhere else the agent needs it.

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 6-parameter read tool with full schema coverage and an output schema, everything an agent needs is present: what it reads, in what order, how to paginate past the cap, what permissions are required, and which siblings to prefer for other intents. No material gap remains.

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 coverage is 100%, so the baseline is 3; the description earns above that by explaining the cross-parameter paging workflow ('re-calling with before set to the id of the oldest message you received'), which the per-field schema descriptions state individually but never compose into a procedure. It doesn't add anything about the around/since interplay beyond what the schema already says.

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?

Specific verb+resource ('Read messages from a text channel or thread') plus an explicit ordering guarantee (oldest-to-newest). It names the sibling tools it is not (discord_search_messages, discord_fetch_pinned_messages), so an agent can route correctly without opening any 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?

Gives explicit when-to-use-what: use this to walk a channel, use discord_search_messages for keyword filtering, use discord_fetch_pinned_messages for pinned-only. It also states the prerequisite permissions (View Channel, Read Message History), which is the main condition for failure.

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