Fetch a signal by its ID to retrieve detailed monitoring data for investigating issues and analyzing agent behavior.
Get a signal by ID.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes |
Changes observed during successful MCP inspections.
v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=true and openWorldHint=true, covering the safety profile (no mutations). The description adds no behavioral context beyond the obvious 'Get', such as return format, error behavior, or potential external dependencies implied by openWorldHint. Since annotations already establish read-only nature, the description is not misleading but offers little added transparency.
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 a single, short sentence with no redundancy or filler. It is front-loaded with the core action and resource, and every word earns its place. This is an example of appropriate conciseness for a simple getter.
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?
With no output schema, the description should explain what the returned signal object contains, but it says nothing about the response structure. It also omits any mention of error handling, prerequisites, or how the ID is generated or discovered. Given the tool's simplicity (one parameter), the description is under-specified and leaves the agent without critical context for interpreting results.
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 0%, so the description must compensate for parameter meaning. The phrase 'by ID' merely restates the parameter name 'id' without explaining what the ID refers to, what format it takes, or how to obtain it. It adds no substantive semantic value beyond what the parameter name already implies, failing to bridge the gap left by the sparse 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 states a clear verb ('Get') and resource ('signal') and specifies the lookup mechanism ('by ID'), making the primary purpose unambiguous. However, it does not clarify what distinguishes a signal from other entities like cases or findings, and it does not differentiate from sibling getters such as invariance_case_get or invariance_finding_get beyond the resource name. This is clear but not fully differentiating.
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 provides no guidance on when to use this tool versus alternatives like invariance_signal_list (to enumerate signals) or invariance_signal_emit (to create signals). It neither states a preferred use case nor exclusions, leaving the agent to infer that it should be used when a specific signal ID is already known. This is minimal and not explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.