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

Adds genuinely non-obvious behavior beyond the annotations: merge semantics (omitted keys keep their value), the "-" sentinel that clears a key, and that undeclared keys/values are rejected rather than silently dropped — a critical failure mode. The clearing behavior is consistent with destructiveHint=true, though the description never states that cleared values are unrecoverable or what permissions are required.

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 sentences, front-loaded with the action, then the merge/quirk semantics, then sibling routing. No restatement of the title or the schema, and every clause carries information the agent needs.

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 only two parameters, no output schema and a nested object, the description covers the mutation contract, validation failure mode, and alternatives well enough to call it safely. The only gap is the success response shape, which it leaves unstated since there is no output schema to lean on.

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% with a nested filter map already documented, so the baseline is 3; the description earns above baseline by explaining the merge contract, the "-" clear convention, and that valid keys/values must come from list-prompt-filters. prompt_id itself is not elaborated, but it needs no elaboration.

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?

Opens with a specific verb+resource: "Set the custom filter values on an existing prompt." It then explicitly delimits itself from the confusable siblings by declaring prompt text immutable and naming move-prompt-to-topic, archive-prompt and restore-prompt as the tools for topic/status. An agent can pick this tool over those without opening any schema.

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 the trigger condition (setting filters on an existing prompt) plus explicit routing for adjacent operations: topic changes go to move-prompt-to-topic, status changes to archive-prompt/restore-prompt. It also points at list-prompt-filters as the required source of valid keys and values, which is a real prerequisite for calling this correctly.

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