agent_update_profile

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

With no annotations provided, the description carries the full behavioral burden and discloses several key traits: both fields are public, the tool is off by default and gated by an environment variable, and it updates identity in the local credential store. It still omits details such as whether updates are partial or full replacement and whether changes are reversible, but it covers the main mutation and access-control behavior.

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?

The description is compact and front-loaded: purpose first, then visibility, then the access gate, then identity context. Every sentence earns its place, with no redundant or filler content.

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?

Given two optional parameters, no annotations, and no output schema, the description covers purpose, visibility, access control, and identity-store behavior. It is nearly complete for a simple mutation tool, though it could clarify partial-update behavior when only one field is supplied.

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%, so the input schema already documents both parameters fully. The description mentions display name and capabilities but adds no format, syntax, or replacement semantics beyond what the schema provides, making the baseline score of 3 appropriate.

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 states a specific verb (Update) and resource (your display name or capabilities), making the tool's function clear. It also adds that this acts as identity in the local credential store, which helps distinguish it from generic profile reads. However, it does not explicitly name sibling alternatives such as agent_get_profile or agent_register_capability, so differentiation relies on the agent's inference.

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 provides an important usage condition: the operation is refused unless the human owner sets VOIDLY_MCP_RELAY_ALLOW_OPEN_WRITES=1. That is useful prerequisite guidance, but it does not state when to use this tool versus alternatives like agent_register_capability or agent_get_profile, leaving alternative selection implied.

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