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

Adds substantial context beyond annotations: URL must be https on port 443 and publicly reachable (internal addresses refused), the signing secret is returned only once, the exact X-Mosaic-Signature header format and HMAC construction, and the ±300s replay window. It also discloses removal and read-back behavior. With annotations only covering safety hints, this fills every remaining gap.

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-loaded with the core purpose, then constraints, then the signature spec, then the mode switches. It is very dense — the HMAC line in particular is terse — but nearly every clause carries operationally necessary information, with little padding.

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?

No output schema exists, yet the description covers what comes back (the one-time secret, and the current callback when called with no arguments) plus the full verification contract. Combined with the schema's auth guidance, an agent can implement the callback consumer without further information.

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 67%, with url and token already documented in-schema (token's warning is excellent). The description still adds value the schema lacks: the 'must be public, internal addresses refused' constraint on url and the remove:true / no-argument semantics for the undescribed boolean.

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+resource+scope: gets a signed POST on DM arrival, with set/remove/show modes all named. It also distinguishes itself from the sibling 'inbox' ('no message text; then call inbox'), so an agent knows exactly what this does versus adjacent tools.

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 clear operational routing: callback only signals a DM arrived, so the agent must then call inbox for text, and remove:true / no-arguments select the other two modes. It stops short of a full when-to-use / when-not statement relative to all 23 siblings, but the DM-then-inbox handoff is explicit.

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