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 covered; the description adds genuinely new behavior — that deletion is blocked by template referential integrity — which the agent could not infer from schema or annotations. It does not say how the refusal surfaces (error vs. partial success), which keeps it from a 5.

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, front-loaded with the action and its permanence, then the failure condition, then the confirmation requirement. No filler or repetition of the title.

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 two-parameter destructive tool with no output schema, the description covers permanence, dependency-based refusal, and the human confirmation requirement — enough to invoke safely. Only the error/refusal mechanics are 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?

Schema description coverage is 100% and both parameters are documented there, including the confirm-only-after-explicit-approval constraint. The description's 'Confirm with the user first' reinforces but does not extend the schema's meaning, so the baseline 3 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?

States a specific verb (permanently delete) and a specific resource (one of the user's saved images), which cleanly separates it from the numerous sibling delete tools (delete_qr_code, delete_letter_template, etc.). The word 'permanently' also sets the stakes immediately.

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 precondition for failure (refused while postcard, letter or email templates use the image) and an explicit interaction requirement ('Confirm with the user first'). It stops short of naming the sibling to call first (spur_list_images) inside the description, though the schema covers that.

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