set_custom_property

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 still adds real value beyond that: it discloses upsert behavior when the property is missing and, critically, that an empty value is a delete path — an agent would not infer that from the schema.

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 short sentences, front-loaded with the action and followed by the two behavioral facts that matter (upsert, empty-deletes). No filler whatsoever.

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 2-parameter mutation with an output schema, the definition covers the essential risk (deletion via empty value) and creation behavior. Only minor gaps remain, such as name-matching rules and permission requirements on the active document.

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 0%, so the description must carry the burden. It explains the 'value' side (empty string means delete) but says nothing about 'name' — case sensitivity, allowed characters, or whether it matches an existing property by exact name.

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 ('Sets a custom property of the active document') and scopes it to the active document, which separates it from generic siblings. It is clearly distinct from the read-only get_custom_properties, though it never names that counterpart.

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?

Usage is only implied: the upsert semantics ('created if missing') tell an agent it need not check existence first, which is a useful cue. But there is no explicit when-to-use / when-not phrasing or reference to alternatives such as get_custom_properties for reading values.

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