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

Annotations declare openWorldHint=true, idempotentHint=false, and readOnlyHint=false, but the description adds nothing about what streaming actually means here (connection lifetime, chunk cadence, termination). It does add genuinely useful operational context the annotations lack: the endpoint and a 10-credit Tier 1 cost. No contradiction with the 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?

A single front-loaded sentence plus three bracketed metadata lines; nothing is padded or redundant. It is terse to the point of under-specification rather than verbose.

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?

An output schema exists, so return-value explanation is not required, and cost/endpoint are covered. What is missing is the streaming-specific behavior an agent needs to call this correctly: delivery mechanism, whether it terminates after the countdown, and how it differs from the eclipse_totality and eclipse webhook siblings.

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 100% and both optional parameters (fields, precision) are fully documented in the schema, so the baseline is 3. The description adds no meaning about compact mode or precision beyond what the schema already states.

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 resource and scope: a countdown to the next 5 eclipses. An agent can tell it produces upcoming-eclipse timing data, though it never contrasts itself with the very similar sibling astroway_stream_eclipse_totality, so sibling differentiation is missing.

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 offers no when-to-use guidance, no prerequisites, and no named alternatives despite a dense sibling set (eclipse_totality, webhooks_eclipse_alert, stream_transit_alerts). Usage is only implied by the name and the '[Group: Real-time Streaming]' label.

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