DM read

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so 'Read-only.' is largely redundant. However, the description adds two genuinely non-annotation facts: the INSSIST PRO license prerequisite and the oldest-first ordering of returned messages, both of which affect whether/how an agent should call it.

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 short fragments with zero waste; the core action and ordering are front-loaded, and the secondary facts (read-only, PRO) follow. Nothing could be removed without losing 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 tool with no output schema, the description conveys shape only loosely ('recent messages, oldest first') and says nothing about how many messages are returned, pagination, or message fields. Given the tool's simplicity and full schema coverage, this is adequate but leaves the return contract underspecified.

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%, with thread_id, instance, and instant all documented in the schema itself (including the pacing semantics of 'instant'). The description adds no parameter-level meaning beyond that, so the baseline of 3 applies.

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 (Read), a specific resource (a DM conversation's messages), and adds scope/ordering (recent, oldest first). This is enough to distinguish it from sibling dm_list (which enumerates conversations rather than reading one thread), though the description never names that sibling explicitly.

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 guidance on when to use this tool versus alternatives such as dm_list, dm_requests, or dm_mark_seen, and no exclusions or preconditions beyond the PRO note. The purpose is self-evident enough that an agent can infer usage, but nothing is stated.

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