Set MyChart Provider

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

Annotations indicate idempotentHint=true, readOnlyHint=false, and destructiveHint=false. The description goes beyond this by disclosing that the setting persists to ~/.mychart-mcp/config.json, that URLs are normalized to the instance root, and that changing providers invalidates saved login sessions in a nuanced way. This additional context about side effects and persistence is valuable and not redundant with 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?

The description is well-structured with a clear opening sentence, an Args section, a Returns statement, and a brief note on persistence. Every sentence serves a purpose, and the length is appropriate for the complexity of the tool. No filler or repetition of schema verbatim.

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 single-parameter configuration tool, the description fully covers what the tool does, where the setting is stored, what it returns, and the effect on sessions. There is no output schema, but the Returns line describes the normalized base URL. Combined with annotations, this is complete and leaves no open questions.

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 100% with the url parameter already described. The description adds meaning by giving concrete examples (e.g., a login page URL), stating that any URL from the provider's site works, and explaining automatic normalization to the instance root. This improves understanding beyond the schema's simple description.

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 opens with a specific verb-resource pair: 'Configure which health system's MyChart site to use.' This clearly distinguishes it from sibling tools like mychart_login or mychart_list_test_results, as it is the only configuration/setup tool. It also states the need to set it once before logging in, reinforcing its purpose.

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 explicitly says 'must be set once before logging in,' which tells the agent when to use this tool relative to mychart_login. It also explains that every hospital system runs its own instance, so this setup is required. However, it does not explicitly list alternatives or 'when-not-to-use' scenarios, missing the full bar for a 5.

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