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

Annotations already declare readOnlyHint/idempotent/non-destructive, and the description goes well beyond them: it states the auth prerequisite ('an attributable user who still belongs to the credential Account'), which fields are read-only, the trial-gating behavior ('every tool, this one included, returns trial_expired'), and that it changes no settings and launches no Scan. This is exactly the extra behavioral context 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?

Purpose and scope are front-loaded and the preconditions follow logically. The long inline field enumeration is partly redundant with the existing output schema, which slightly inflates length, but every other sentence carries load.

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 no-arg read tool with an output schema and rich annotations, the description covers everything an agent needs: what it returns, its scope boundary, auth requirements, trial-expiry failure mode, and side-effect profile. Nothing material is left unspecified.

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?

With zero parameters the baseline is 4, and the description usefully preempts an agent from inventing an accountId argument by stating 'Takes no Account ID.' No further parameter semantics are needed or possible.

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+resource ('Read the Account this credential belongs to') and enumerates the exact fields returned (saved name, type, website, licenseTier, billingCycle, trialEndsAt, accessState), so an agent knows precisely what this returns. The clause 'Takes no Account ID and does not select another Account' explicitly disambiguates it from the ID-scoped siblings like get_client, get_site, and get_portfolio.

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?

Gives real usage context: 'Read before editing and after an uncertain update,' plus the scoping rule that it never selects another Account. It falls short of naming the alternative tool an agent should use when it does want another account's data, so the when-not is implied rather than routed.

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