pubchem-mcp-server

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

Annotations declare readOnly/idempotent/openWorld traits. Description adds valuable operational constraint not in annotations: 'Up to 10 per call' (batch limit). Also clarifies the specific ID formats expected for each entity type, adding context beyond the structured hints.

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?

Two sentences, zero waste. Front-loaded with action verb ('Get'), follows with scope clarification ('Supports...'), and ends with operational constraint ('Up to 10'). Every clause earns its place.

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?

Given 2 parameters with 100% schema coverage, existing output schema, and read-only annotations, the description provides sufficient context: purpose, entity scope, and batch limits. No gaps requiring additional explanation for correct invocation.

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 has 100% description coverage with detailed identifier format examples. Description reinforces entity type semantics ('assays (AID)', etc.) but largely echoes the schema documentation. With complete schema coverage, baseline 3 is appropriate as description adds minimal semantic depth beyond structured fields.

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 specific verb ('Get') + resource ('descriptive summaries for PubChem entities') + scope ('by ID'). Explicitly lists supported entity types (assays, genes, proteins, taxonomy) which clearly distinguishes this from compound-focused siblings like pubchem_get_compound_details.

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?

Provides clear context by enumerating supported entity types (AID, Gene ID, UniProt, Tax ID), implicitly signaling this is not for compounds. However, lacks explicit 'when not to use' guidance or direct sibling comparison (e.g., does not explicitly state 'for compounds use pubchem_get_compound_details').

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