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

Goes well beyond the annotations by disclosing that SMS comes from an automated number and cannot be replied to, that Booksy appends a profile link, and that confirmation is on by default. It also flags the openWorld reach and repeats the confirmation requirement, reinforcing openWorldHint=true with concrete consequence.

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?

The first two sentences are largely redundant ('Send one message ... by email, SMS or push notification' followed by 'Sends one Message Blast ... by email, SMS or a push notification'). Behavioral detail in the middle is valuable, but the opening wastes space on repetition.

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 mutation tool with annotations covering safety and openWorld behavior, the description covers recipients, channels, confirmation requirements, and API-key access. With no output schema, it gives enough for an agent to call it correctly; only return/confirmation-response behavior is unspecified.

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 channel enum values, message text, and client_ids sourcing are already documented in the schema. The description restates the channel list and recipient source but adds no parameter-level syntax or constraints beyond that, so the baseline 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 (Send), resource (one message/Message Blast), the delivery channels, and the recipient set ('the clients you list'). An agent can distinguish this broadcast tool from booksy_add_client or booksy_list_clients 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 clear operating context: recipients must come from list_clients, each call is confirmed by default (switchable off), and the user must confirm before each send because it reaches other people. It does not name a sibling alternative, but no other Booksy messaging tool exists, so the routing risk is low.

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