get_aws_member_account

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

Annotations already declare the operation read-only and non-destructive. The description adds meaningful return semantics: identity, onboarding status, 30-day ESR/savings, YTD/lifetime totals, potential savings, and the data behind Cost Summary and Commitment Coverage charts. It also notes that lifetime is bounded by the parent organization's onboarding start. No annotation contradiction.

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 field list is well-structured and valuable, and the core purpose appears early. However, the first sentence is irrelevant marketing fluff about PerfectScale capabilities that doesn't describe what this tool does; it should be removed. The description is longer than necessary because of this misleading opener.

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 compensates well by enumerating the Overview fields in detail. However, it leaves required parameter semantics to the schema and does not clarify how managementAccountId and memberAccountId relate, nor does it explicitly point to list_aws_member_accounts for the list-item field definitions.

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 only 25%, and the tool description does not mention managementAccountId, memberAccountId, customerContext, or X-Tenant-Id at all. The parameter names and regex patterns provide minimal clues, but for a tool requiring two 12-digit account IDs, the description should clarify which is the parent management account and which is the target member account.

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 clearly states that the tool returns a single member AWS account with the same list-item fields as List member accounts plus Overview time series data, and it contrasts this with fetching every member account. However, the opening sentence about evaluating commitments, planning purchases, and optimizing cloud costs is off-purpose and could mislead an agent about the tool's actual operation.

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?

It explicitly says to use this when a single member Console Overview is needed in one call 'without fetching every member account', which implies the sibling list tool for bulk retrieval. The guidance is clear but doesn't explicitly name the exact sibling or provide exclusion cases.

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