add_suppression

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

With no annotations and no output schema, the description carries the full behavioral burden. It discloses the core effect (nothing gets sent), but says nothing about idempotency for an already-suppressed address, whether it applies to all send paths including batch, required permissions, or reversibility. One sentence of effect is thin for a mutation tool.

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?

A single sentence with zero filler, front-loaded with the verb and resource and ending with the consequence. Nothing to trim.

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 simple two-parameter mutation the description covers purpose and outcome, but leaves open what happens when the address is already suppressed and how this interacts with sends in flight. Adequate as a minimum, not complete.

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% and both parameters are documented there, including the reason field's accepted values (manual, bounce, complaint). The description adds no parameter meaning 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 ('Add') and resource ('suppression list') plus the effect ('nothing is sent to it'). It is distinguishable from list_suppressions and remove_suppression by the verb, though it never names them 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?

The intended use (block all delivery to an address) is implied by the effect clause, but there is no explicit when-to-use guidance, no mention of bounce/complaint-driven versus manual suppression workflows, and no pointer to remove_suppression for reversal.

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