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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds genuinely new behavioral context beyond that: the schema is account-wide and identical across projects, so the agent knows a single call suffices regardless of which project it intends to query. It stops short of 5 because it doesn't say whether the result is cached or how the embedded query notes are formatted.

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, front-loaded with the resource and contents before the cross-project note. The second sentence is slightly redundant ('shares this schema' / 'same whichever one you query') but reinforces a fact an agent could otherwise waste a call verifying.

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?

With no output schema, the description must convey what comes back, and it does: tables, indices, and notes on querying. For a zero-parameter, read-only introspection tool this is nearly everything an agent needs; only the exact return structure and whether the notes are part of the same payload remain unspecified.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. The statement that the schema is shared across all projects usefully explains why no project identifier is needed.

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 gives a specific verb and resource: 'Return the SQL schema (tables and indices) of a RevScope project's analytics database.' It also scopes the content (tables, indices, plus query notes), which is more precise than the name alone. It does not explicitly contrast with siblings like run_query, so it stops short of a 5.

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?

Usage is only implied: the phrase 'with notes on how to query it' suggests calling this before writing queries against the database, but the description never says when to call it versus run_query or list_projects. There are no explicit preconditions or exclusions, leaving the agent to infer the workflow.

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