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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is supplied. The description adds one genuinely useful behavioral guarantee beyond the annotations — 'Never returns variable values' — which bounds what the agent can expect from sensitive data. It does not mention permission or auth requirements, so the addition is real but modest.

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 that names the resource and its returned components before the caveat. Very little waste; the trailing 'Never returns variable values' clause is short and 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?

An output schema exists, so return values need not be explained, and the read-only annotation covers the mutation risk. What remains missing is enough parameter meaning for 8 params at 13% coverage and any hint of how this differs from the several overlapping Railway status siblings — adequate for a read tool, but not fully complete.

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 8 parameters and only 13% schema description coverage, the description must carry the load, and it does not. It obliquely names the optional sections (domains, metrics, recent deployments) without mapping them to the include_domains, include_metrics, deployment_limit, or include_recent_deployments flags, and it says nothing about the format of the required project/service/environment identifiers.

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+resource+scope: 'Detailed status for a service in an environment,' and lists the content sections (service instance, latest deployment, optional domains/metrics/recent deployments). It is clear what the tool returns, but it does not distinguish itself from close siblings such as railway_project_status, railway_health_summary, or railway_deployment_get.

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 explicit guidance on when to choose this over railway_project_status, railway_health_summary, railway_dashboard, or railway_domains/railway_metrics_summary, which appear to cover the same optional sections. The only usage signal is implicit in the word 'Detailed,' leaving the agent to infer routing.

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