compose_config

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

Annotations (readOnlyHint=true, destructiveHint=false) already cover the safety profile, and the description adds substantial behavioral context beyond that: it does not raise on non-zero CLI exit, `config` may be None on failed render, the agent should inspect `raw.stderr`, and project_dir is copied to the target host when no local plugin exists. These are non-obvious behaviors that materially affect how an agent should invoke and interpret the tool.

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 and front-loaded: a one-sentence purpose, a usage sentence, an error-behavior note, then a compact args list and returns spec. Despite covering 6 params and return details, every line earns its place. The formatting makes it scannable, and the length is appropriate for the tool's complexity.

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 6 optional parameters and no output schema, the description carries full burden for return-value documentation—and it succeeds. It details the return dict structure ('config' plus 'raw'), the parsed-dict behavior when format='json', the fallback to raw stdout text, and the failure mode. Combined with good annotations and clear purpose, nothing essential 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 0%, so the description must compensate—and it does comprehensively. The 'args:' section explains all 6 parameters with meaningful semantics: project_dir (default + host-copy behavior), files (repeatable, `-f`), project_name (override), profiles (activation), services_only (`--services`), and format (yaml/json). This fully compensates for the empty schema descriptions.

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: 'Render the canonical compose configuration after merges, profiles, and variable substitution.' This precisely identifies what the tool does and distinguishes it from siblings like compose_up (which applies the config) and compose_ps (which inspects running services). The scope is clear: it is a dry-run/validation rendering tool.

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 provides explicit usage guidance: 'Use it to validate compose files and see exactly what the CLI will run before compose_up.' It names the primary use case, the timing (before compose_up), and the sibling alternative (compose_up) in a single directive sentence. This clearly positions the tool against its sibling.

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