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

Adds substantial behavior beyond the readOnly/idempotent annotations: default summarization above 60 snapshots, exactly which aggregates the summary contains, the full=true escape hatch, and definitions of the SHRUNK and RECOVERED flags that appear in results. This is the kind of return-shape and semantics disclosure the annotations cannot carry.

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?

Front-loaded with what is returned, then the summary/full behavior, then flag definitions, then usage — a logical order with no filler. The flag definitions are dense but each sentence earns its place; minor cost is the telegraphic 'SHRUNK:'/'RECOVERED:' phrasing.

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 6-param read-only listing tool with no output schema, the description covers the return payload shape, the summary-vs-full behavior, and the meaning of result flags — precisely the information an agent would otherwise lack. Pagination is left to the schema's limit/offset descriptions, which is acceptable.

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 coverage is 67% and the description clarifies full=true ('lists them all') and the summary threshold, adding real meaning. It adds nothing for limit, offset, to, or from beyond what the schema already documents, so the baseline 3 is right.

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 and resource (list snapshot dates for one monitor) plus what each snapshot contains (size on disk). It is clearly distinguishable from siblings like get_snapshot (single) and get_history by naming the monitor-scoped listing semantics.

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?

Explicitly says 'Use it to see how far the history goes and pick dates', which frames the retrieval purpose, and explains the summary/full distinction. It does not name sibling alternatives (get_snapshot, get_history) or state when not to use it, so it stops short of a 5.

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