message_send

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

Annotations only carry openWorldHint=false and destructiveHint=false; the description adds meaningful context: delivery is async and the recipient sees it only when they call message_inbox(). The deprecation status is also disclosed. No contradiction with annotations.

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?

Well-structured and front-loaded: deprecation warning first, then purpose, usage, then args. Every sentence earns its place, and the critical deprecation signal leads the description.

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?

Complete for an async messaging tool: deprecation, delivery timing, recipient behavior, and param semantics are all covered. An output schema exists, so return-value details need no elaboration. Could add what happens on failure, but nothing essential is missing.

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 schema already documents all three parameters. The description's Args section largely mirrors the schema; the only added value is noting subject 'helps the recipient triage.' Baseline 3 is appropriate since the description doesn't substantially enrich what the schema already provides.

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 ('Send a message to another agent's inbox') and opens with a DEPRECATED notice that clearly differentiates it from siblings like message_inbox, message_mark_read, and message_list. The recipient-routing detail (message_inbox()) ties it to the matching sibling.

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?

Explicitly lists when to use it ('async coordination: delegating work, sharing a finding, asking a question, or notifying another agent that something is ready') and when NOT to ('DEPRECATED... not where new work should go'). Names the receiving-side sibling (message_inbox).

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