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

Annotations only provide destructiveHint=true, so the description adds real value by clarifying that the action 'changes live policy behaviour' and by naming the underlying endpoint. It still omits auth requirements, rate limits, and any indication of reversibility or response behavior.

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?

Three tight sentences, front-loaded with the action, and each sentence earns its place by adding scope, consequence, or endpoint detail. No filler or redundancy.

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 minimal annotations and no output schema, the description covers the essential 'what' and the key consequence of the write. It stops short of covering permissions or return information, which is a modest gap rather than a critical one.

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 every one of the 7 parameters is already documented in the schema (including required/optional and the author_type enum). The description adds only the endpoint path, which lightly implies list_id's role; baseline 3 is correct.

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 ('Add an entry to a list') and grounds it with concrete examples (block an IP or an email), so the function is unambiguous. It implicitly separates itself from siblings like update/archive_list_item, but never names an alternative, so it falls short of full sibling differentiation.

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 usage context via the blocking example and flags that this alters live policy, which tells the agent when this is the right action. It offers no explicit when-not or alternative-tool guidance (e.g., when to use update_list_item instead).

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