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

With no annotations, the description carries the full burden and does substantial work: it discloses the side effect that a pending invite is created for non-Ventru recipients, that a thread is started, that replies are free, and that from+token produce a verified sender. It omits failure modes (what happens with an invalid token or unknown domain) and any rate limits, keeping it at 4.

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?

Four tight sentences with the core action front-loaded, followed by thread/cost behavior, sender verification, and the invite fallback. No sentence is redundant and nothing is buried.

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 7-parameter mutation tool with no annotations and no output schema, the description covers the important unknowns: the invite side effect, thread continuation, and verified-sender mechanics. It does not describe what the call returns (thread ID, delivery status) or error conditions, which leaves a modest 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 coverage is 71%, and the description adds real meaning beyond it: it clarifies the accepted formats for 'to', explains where 'from' and 'token' come from (ventru_register), and states that threadId continues an existing thread. The 'intent' and 'router' parameters are left to their schema descriptions, which already cover them adequately.

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 and resource ('Send a signed message to any Ventru address') and enumerates the accepted address forms (@name, agent:..., verified business domain). That plus the thread semantics distinguishes it cleanly from ventru_inbox (reading) and ventru_find (discovery).

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 operational context: pass your own address and token from ventru_register for verified sending, and use threadId to continue a thread rather than start a new one. It stops short of an explicit 'use X instead when…' exclusion against siblings like ventru_create_route, so it lands at 4 rather than 5.

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