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

Annotations only declare readOnlyHint=false, openWorldHint=true, destructiveHint=false. The description goes well beyond: text messages cost announcement credits (1 per 160 chars, capped at 800 chars), email/portal are free, a plan requirement exists, each call defaults to confirmation, and it reaches other people so the user must be asked. This is exactly the cost/auth/irreversibility context an agent needs before a write.

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 the core action correctly, but repeats the credit model twice ('Texts use announcement credits' then 'Text messages use announcement credits (1 per 160 characters)... and are capped at 800') and splits the confirmation rule across two sentences. Informative but with avoidable duplication.

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 no output schema, the description covers the prerequisites (plan tier, API key), costs, confirmation behavior and audience scope that govern a correct call. It does not describe what a successful send returns or how to know delivery succeeded, which is the remaining gap.

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 baseline by explaining channel-specific behavior — that the 'channels' values email and portal are free while text consumes credits and is length-capped — which adds meaning the schema's flat 'Any of email, text, portal' does not convey.

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 (sends) and resource (announcement) plus the audience (tenants) and delivery channels (email, text, portal), and scopes the blast radius (full portfolio or chosen properties). An agent can tell this apart from sibling read tools like doorloop_list_communications at a glance.

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 contextual conditions: it targets tenants of the whole portfolio or selected properties, and notes the Pro/Premium plan prerequisite. It does not name an alternative tool or state when-not to use this (e.g. versus other communication channels), so it stops short of the explicit routing that a 5 requires.

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