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

Annotations declare destructiveHint=true, and the description adds the crucial mitigation that this is a partial update where untouched fields are preserved, plus the credential restrictions. That is real behavioral context beyond the annotation, though it does not cover response behavior or failure modes.

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 capability, then the partial-update rule, then the hard limit. Every sentence carries information and nothing is repeated from the schema.

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 14-parameter mutation tool with no output schema, the description covers scope, partial-update semantics, and prohibited fields, which is enough to invoke it correctly. It leaves out what the response contains and whether special permissions are needed, minor gaps given the absence of an output schema.

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 baseline is 3; the description earns a bump by grouping the 14 parameters into navigable buckets and independently flagging the username/password/login prohibition that the schema only partially mirrors via the access_permissions note.

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 ('Edit an existing person's details') and enumerates the editable domains (name, contact info, category, flags, family, extra fields). This cleanly separates it from elvanto_create_person and elvanto_get_person without needing the 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 clear operating context ('Only the fields you pass change') and explicit exclusions ('Cannot touch username, password or login status'), which tells the agent both how to call it and where its authority ends. It stops short of naming sibling alternatives or stating permission prerequisites, so it is not quite a 5.

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