fdsn_get_earthquake_by_id

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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds crucial behavioral context: the eventid is an opaque, provider-specific string that must exactly match a query result, and it lists available datacenters with a default and a non-exhaustive set supported by ObsPy. This enriches understanding without contradicting 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?

The description is compact and front-loaded: first sentence states the primary purpose, next specifies the return payload, then provides usage restrictions, and finally datacenter options. Each of the four sentences adds distinct value with no wasted words.

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?

Given that an output schema exists and handles return-value details, the description covers all necessary context: purpose, input provenance rules, available datacenters, and alternative-tool routing. For the complexity of a simple lookup-by-ID tool, this description is sufficiently complete to guide correct invocation.

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?

With 0% schema description coverage, the description fully compensates. It defines the eventid's opaque, provider-specific nature and mandates copying it verbatim from a prior result, and it explains the datacenter parameter with named options and the default value. Both parameters receive meaningful elaboration beyond the bare schema.

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 uses a specific verb and resource: 'Get basic information about a specific earthquake event by event ID', and lists the returned items (preferred origin, preferred magnitude, station magnitudes, amplitudes). It clearly distinguishes from sibling tools by directing users to 'specialized tools' for detailed data like all origins or arrivals.

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 explicitly states when to use this tool (basic information) and when to avoid it (detailed data), naming the specialized alternatives. It also gives an essential prerequisite: the eventid 'MUST be copied verbatim from a prior fdsn_query_earthquakes result' and warns against inventing values. This is clear when-to-use and when-not-to-use guidance.

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