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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral detail — that supplying ledger_id flags the default account and exposes is_default/default_expense_account_id — but says nothing about ordering, pagination, or what happens when the workspace has no accounts.

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?

Two sentences, front-loaded with the resource definition, then the usage path, then the optional-parameter effect. Every clause carries information an agent needs; nothing is padded.

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 zero-required-parameter read tool with annotations covering safety and no output schema, the description carries its weight by describing the return fields (is_default, default_expense_account_id) and the id-resolution workflow. Nothing essential is missing.

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 the ledger_id definition already exists, but the description adds what passing it actually produces (the default-account flag) rather than merely restating the parameter. That is useful meaning beyond the schema.

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 the workspace's expense accounts") and defines the concept inline as the source-of-money attribution, with examples of what an account is. That makes it distinguishable from siblings such as list_ledgers or list_household_members without needing their schemas.

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 an explicit trigger: use this to resolve the numeric account id before passing expense_account_id to record_expense, which names the downstream sibling. It lacks an explicit "when not to call" (e.g. if you already have the id), but the context is otherwise clear.

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