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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is known; the description adds the genuinely useful post-condition that already-booked transactions are unaffected by the deletion. The trailing 'Free.' is opaque and adds no usable behavioral signal.

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?

Three short sentences with the action front-loaded and no filler. The final fragment 'Free.' is cryptic enough that it mildly undercuts an otherwise tight, well-ordered description.

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 single-parameter delete tool with annotations covering destructiveness and idempotency plus a fully described schema, the description supplies the one missing piece an agent would want: that historical bookings persist. Only the opaque 'Free.' and lack of sibling routing keep it from being complete.

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?

Only one parameter exists and the schema fully documents it ('The rule's name, e.g. "Bank fees"') at 100% coverage, so the baseline of 3 applies. The description adds nothing about the name identifier (e.g., whether it must match exactly or is case-sensitive).

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 uses a specific verb and resource ('Delete a bank rule') that maps one-to-one with the tool name and cleanly separates it from siblings like books_save_bank_rule, books_list_bank_rules, and books_apply_bank_rules.

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?

The description never states when to delete a rule versus editing it via books_save_bank_rule, nor whether deletion is reversible or requires prerequisites. The only adjacent statement, 'What it booked stays booked,' is a consequence note rather than usage guidance.

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