snapshot

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

Annotations already declare readOnlyHint, destructiveHint=false and a closed-world scope, so the safety profile is covered. The description adds useful temporal context (a 5-minute averaging window, default to all discovered outputs) beyond the annotations, but says nothing about refresh cadence, staleness guarantees, or failure behavior.

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?

Two terse sentences that front-load the core semantic (what value is returned) before the optional filtering behavior. No filler wording; slightly clipped grammar but nothing wasteful.

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 single-optional-parameter read tool with annotations covering safety and no output schema required, the description supplies what an agent needs: the value definition, the time window, and the default scope. Only unit/return-format detail is absent, which is acceptable given the schema coverage.

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%, so the 'channels' parameter and its omission default are already documented. The description restates the default behavior and adds the nuance that outputs are 'discovered', which is marginal added value on top of the 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 concrete resource and semantics ('latest instantaneous power, a single averaged value over the last 5 minutes'), which clarifies the otherwise opaque tool name 'snapshot'. It does not, however, explicitly distinguish itself from siblings like energy_by_interval, query, or watch, so an agent must infer the routing.

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?

Usage is implied ('latest instantaneous power') and the optional channel restriction is described, but there is no explicit when-to-use guidance or exclusion relative to query, energy_by_interval, or sample_waveform. The agent must infer that this is the lightweight current-reading tool.

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