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

Annotations already declare destructiveHint=true, idempotentHint=true, readOnlyHint=false. The description goes beyond them by disclosing the authorization model (author-only edits) and two specific failure modes with error codes, which is exactly the kind of auth/constraint context the annotations cannot express.

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 critical operation ('Rewrites the note's text') is front-loaded, followed by the permission constraints. The only waste is the first line repeating the title 'Edit a note', a minor redundancy in an otherwise tight description.

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 destructive mutation tool, the description covers the key behavioral concerns: authorization rules and immutable-note errors. With 100% schema coverage and safety annotations present, it is nearly complete; it only omits any note about the return/confirmation behavior, though no output schema exists to carry that.

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 all four parameters (agent_id, contact_id, note_id, text) are already documented in the schema, including the text length bounds and error codes. The description adds no parameter-level syntax or format meaning beyond that, so the baseline of 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?

The description states a specific verb+resource: 'Rewrites the note's text'. This makes it immediately distinguishable from create_contact_note (which authors a new note) and list_contact_notes (which reads them). An agent can identify the operation without ambiguity.

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?

It clearly articulates the when-not conditions: only the note's author may edit ('403 not_note_author' otherwise) and system notes cannot be edited ('403 system_note_read_only'). It does not explicitly name a sibling alternative, but the preconditions are strong enough to route an agent correctly.

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