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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuine behavioral detail beyond them: substring matching semantics against "owner/repo", a 10-result cap, most-starred-first ordering, and the fact that each hit carries an interactive diagram link.

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?

Four front-loaded sentences with no filler: purpose, matching semantics with examples, use cases, and the scope limitation. Each sentence contributes distinct information and the ordering puts the core capability first.

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 two-parameter, no-output-schema search tool, the description covers purpose, matching semantics, ordering, result cap, returned artifact, and scope exclusions. Nothing an agent needs to invoke it correctly or interpret results is missing.

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 the baseline is 3, but the description adds matching behavior the schema does not state clearly: that any part of "owner/repo" is matched, with concrete example fragments ("langchain", "vercel/", "react-native"). The limit parameter's default and range are left to the schema, which handles them.

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 (Search) and resource (GitDiagram's library of architecture diagrams for public GitHub repos), with the searchable field (owner or repository name) made explicit. It is clearly distinguishable from siblings like get_repository_diagram, which fetches one diagram rather than searching.

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 two concrete use cases (resolving a project name to its exact owner/repo, and listing repos of an owner or topic that already have diagrams) plus an explicit exclusion: it searches names only, not code or file contents. It stops short of naming the sibling tool to use for retrieval, so it is clear but not fully routing.

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