contacts_block

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

Annotations already declare destructiveHint=true and openWorldHint=true, and the description earns credit by adding context beyond them: it warns that the action 'reaches other people on the platform, deletes, or redirects data' and requires explicit user confirmation. It does not describe reversibility or whether unblocking restores the relationship, but the added confirmation requirement is genuinely useful for a destructive mutation.

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-loaded with the purpose, followed by the confirmation instruction and an endpoint/protocol footer. Three compact lines with little waste, though the transport metadata (POST/gRPC/socket) is arguably more for the caller than for tool selection.

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 destructive, open-world mutation the safety context is decently covered by annotations plus the confirmation instruction, and no output schema exists to explain. However, the total absence of parameter meaning for a 2-param required schema leaves a real 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 description coverage is 0% and the description says nothing about channelId or contactId, nor which channel semantics apply. For a 2-parameter tool the description fails to compensate for the schema gap, leaving both parameters documented only by their example values.

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 ('Block') and resource ('a contact on the platform'), which cleanly separates it from the sibling contacts_unblock. It does not explicitly name that sibling, so it stops short of the 5 anchor, but the action is unambiguous.

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 description adds a confirmation instruction ('say exactly what will happen and get the user's confirmation first') that guides invocation behavior, but it gives no when-to-use guidance relative to alternatives such as contacts_delete or contacts_update_status. Usage is implied rather than specified.

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