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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the safety profile is covered; the description adds genuinely new behavior: only supplied fields are sent (partial update, so omitted fields are preserved) and existing proposals retain their own copy. It stops short of stating irreversibility or permission requirements, but it clears the lower bar set by the annotations.

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 terse, front-loaded clauses — write intent, update semantics, proposal-copy caveat — with the endpoint last. Nothing is wasted and no sentence restates the title.

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 an 8-parameter destructive mutation with no output schema, the description covers intent, partial-update behavior, side effects on proposals, and the transport endpoint — enough to call it safely. Gaps are minor: no mention of response content or whether renaming affects fees already attached to proposals.

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 75% and already documents fee_id, feetype, amount, quantity, unit and description. The description contributes the optionality contract ('only the fields you pass are sent'), which otherwise has to be inferred from the schema's single required field, though it adds no field-level detail beyond that.

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 ('change a saved fee') plus the endpoint PUT /fees/{id}.json. The clause 'Proposals that already use it keep their own copy' implicitly separates it from the sibling bidsketch_update_proposal_fee, which edits the fee instance inside a proposal rather than the saved library fee.

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 'WRITE' marker and partial-update phrasing imply when to reach for this tool, but there is no explicit guidance on when to use it versus bidsketch_create_fee or bidsketch_update_proposal_fee, nor any stated prerequisites (e.g., fee must already exist).

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