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

Annotations cover idempotency, non-destructiveness and closed-world scope, and the description adds genuinely new behavior: skipped existing/invalid values, per-value type inference, and the main-workspace-only constraint on global scope. It does not say what the call returns (counts of added vs skipped), which is the main 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-loads the core action and batch ceiling, then layers constraints in a compact block with no filler. The final sentences are slightly dense and chain multiple clauses, but every sentence carries load-bearing 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 two-parameter write tool with no output schema, the description covers input rules, scope semantics, skip behavior and retry safety well. The one omission is the shape of the response (e.g., how many were added vs skipped), which an agent would want to know for verification.

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, but the description adds real meaning beyond the schema: how each value's type is inferred from the presence of "@", and that scope defaults to workspace while global requires the main workspace. This exceeds what the enum description conveys.

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 (adds) and resource (suppression/blocklist entries) with the batch size ceiling, and is instantly distinguishable from siblings like remove_blocklist_entries, get_blocklist_entry and add_leads. The per-value type inference rule further pins down exactly what the tool accepts.

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 a concrete use case (carrying over a suppression list from another sending platform) and a retry-safety condition, plus the scope default and the restriction that "global" only works from the main workspace. It stops short of naming the sibling tools (remove_blocklist_entries, update_blocklist_entry) an agent might confuse it with, so not a full 5.

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