Set a custom field such as Media Condition on a Discogs collection instance; validate dropdown values via get_collection_fields and dry-run before applying.
Set a custom field (e.g. Media Condition) on a collection instance. For dropdown fields the value must be one of the options from get_collection_fields. Dry-run by default.
| Name | Required | Description | Default |
|---|---|---|---|
| value | Yes | ||
| dry_run | No | ||
| field_id | Yes | ||
| release_id | Yes | ||
| instance_id | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the safety profile (not read-only, idempotent, non-destructive, open-world), so the description need not restate it. It adds genuinely useful behavior beyond that: values are validated against the dropdown option set from get_collection_fields, and the call is a dry-run unless explicitly applied.
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 action and with zero filler. The trailing 'Dry-run by default' is slightly detached but still earns its place as a critical behavioral note.
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?
There is no output schema and no annotations covering auth or side effects, and 5 parameters are undocumented at 0% coverage. The description never states what a dry-run returns, whether an existing field value is overwritten, or how release_id and instance_id relate, so an agent must infer the invocation contract.
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 carries the full burden and only partially discharges it. It explains the constraint on 'value' (must be an option returned by get_collection_fields) and the dry_run default, but release_id, instance_id and field_id are left with no meaning beyond their names.
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 ('Set a custom field ... on a collection instance') and scopes it to a collection instance rather than a release, which separates it from the release-level siblings. It also names the related tool get_collection_fields, so an agent can place it in the workflow without opening 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 context: use get_collection_fields to obtain valid options for dropdown fields, and the operation is dry-run by default. It does not, however, say when to flip dry_run=false or compare itself against sibling mutators such as add_to_collection or move_collection_item.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.