send_message

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

With no annotations, the description carries the full behavioral burden. It goes beyond a simple 'send' statement by revealing that messages are always queued in the magents mailbox and that delivery may use native IPC or fall back to a supervised headless CLI. These are non-obvious behaviors that affect agent expectations, even though error behavior is not fully specified.

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?

The description is two concise, front-loaded sentences with no redundant phrasing. The core action, target scope, preferred execution method, and queuing behavior are each stated once, and every clause earns its place.

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 send operation, the description covers the main intent, supported targets, and delivery behavior, and no output schema exists so return-value detail is not expected. However, it omits error behavior for invalid or missing sessions, how to confirm delivery, and explicit guidance that a caller likely needs await_reply to receive responses—especially given the sibling tool list.

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 only 50%: 'to' has a description, but 'message' has none. The tool description adds no parameter-level details—it just repeats the word 'message' and mentions 'existing chat,' which does not meaningfully clarify formats, limits, or target resolution beyond the schema's existing gloss.

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?

The description states a specific action ('Send a message') with a clear resource ('existing ... chat') and enumerates the supported client types, so an agent immediately knows the core function. It does not explicitly distinguish itself from sibling tools like reply or spawn_session, so it stops short of a 5.

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 implies this is for existing conversations rather than creating new ones, and it offers implementation guidance (native IPC preferred, headless CLI as fallback). However, it never explicitly says when to choose send_message over reply, handoff, or spawn_session, nor does it mention prerequisites or exclusions.

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