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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered without the description. The description does add one genuinely useful behavioral fact not in annotations: the 10-credit Tier 1 cost. However, for a streaming tool it says nothing about stream termination, error semantics, or partial delivery, which is the behavior an agent most needs here.

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?

It is short and the core statement is front-loaded, so nothing is wasted. But the two bracketed metadata lines are boilerplate and the resulting length is too thin for the tool's complexity, so brevity here reads as under-specification rather than tightness.

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 tool with 5 parameters (including a nested arbitrary 'args' object), no output schema, and an opaque streaming return, the definition is far too thin: it never explains what the streamed envelope contains, how the stream ends, or how 'args' maps to the target tool. An agent must guess at most of the call contract.

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 only 40%: 'tool' (the sole required parameter) and 'args' carry no description, and 'language' has only an enum. The description supplies zero parameter guidance, so it fails to compensate for the coverage gap on a 5-parameter tool with a nested free-form object.

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?

It pairs a specific verb ('SSE-stream') with a resource ('tool call envelope'), which is more than a tautology, but 'tool call envelope' is unexplained jargon and the definition does nothing to separate it from close siblings like astroway_mcp_streaming or astroway_mcp_tools_list. An agent cannot tell from this text which one to pick.

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?

There is no statement of when to use this tool, when not to, or what alternative exists for the same need. The only context is the group/cost tag, which tells the agent a price but not a use case.

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