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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is fully covered structurally. The description adds the substantive point that prices are monthly and tied to plan tiers, but says nothing about freshness of pricing or workspace scoping side effects; with annotations doing the heavy lifting, this is adequate rather than rich.

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 tightly packed sentence pair that front-loads the return scope before the usage conditions. Nothing is redundant, though the parenthetical feature list makes the opening clause dense enough to slow a first read.

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?

No output schema exists, so the description carries the burden of describing returns — and it does, naming currentPlan, tier prices, and per-tier Sightglass features. It stops short of stating whether pricing is static or account-specific, but an agent has enough to call and interpret it correctly.

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?

There is one parameter with 100% schema description coverage, and the schema already tells the agent to source workspaceId from list_workspaces. The description contributes no additional constraint on the parameter, so the baseline 3 for fully documented schemas applies.

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 precisely enumerates what the tool returns: the workspace's currentPlan, the Starter and Pro monthly prices, and which Sightglass capabilities each tier unlocks. That specificity clearly separates it from siblings like start_plan_upgrade, though it opens with a noun phrase rather than an explicit verb, leaving the 'get' framing implicit.

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?

Three concrete activation triggers are given: a result names a locked field or higher plan, the user asks about upgrading, or the user reports a completed upgrade to confirm. There is no explicit exclusion or pointer to start_plan_upgrade as the action-taker, so the agent must infer the read-vs-mutate boundary from the sibling name alone.

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