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

Annotations already declare readOnly, idempotent, non-destructive, so safety is covered. The description adds meaningful context beyond that: 'Metadata only' rules out returning table data, and it enumerates the metadata categories returned (partition spec, sort order, snapshots with rows added/removed). This is real added value, though it omits any cost/permission caveats.

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 trigger sentence is well front-loaded, but the central 'sentence' is a sprawling, comma-and-semicolon-separated fragment listing return fields without clear hierarchy. It is information-dense rather than padded, yet the structure makes it hard to parse quickly.

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 carries the return-value burden and largely discharges it, enumerating the field groups an agent will receive. Combined with annotations covering the safety profile and a 100%-documented schema, this is nearly complete; only snapshot pagination/preview semantics and failure modes are left implicit.

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 100%, so baseline is 3, but the description adds semantic meaning to `snapshots` by explaining what each snapshot contains (commit time, operation, rows added and removed) and reveals the derived ingestion-cadence use case. It also clarifies the `agents_md` output source, which enriches the `table` parameter's context.

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 opening sentence gives a specific trigger (user asking what a table's columns are or mean) and the resource (one table), and 'Metadata only' separates it from data-returning siblings like query. However, the second sentence is a grammatical fragment listing returned fields, which muddies rather than states the purpose. An agent can still identify it as the table-metadata sibling of list_tables.

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 states when to use it ('when the user asks what a table's columns are or mean') and clarifies the interaction with read_agents_md by noting the tool returns `agents_md` while read_agents_md retrieves the file. No explicit when-not or pagination/limit guidance, but the read/write boundary is implied by 'Metadata only'.

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